diff --git a/internal/api/bindings.h b/internal/api/bindings.h
index 6bb960b4d..bf03c9e24 100644
--- a/internal/api/bindings.h
+++ b/internal/api/bindings.h
@@ -139,8 +139,9 @@ typedef struct ByteSliceView {
  *     // …
  *     # let mut error_msg = UnmanagedVector::default();
  *     # let mut used_gas = 0_u64;
+ *     # let read_db = db.vtable.read_db.unwrap();
  *
- *     let go_error: GoError = (db.vtable.read_db)(
+ *     let go_error: GoError = read_db(
  *         db.state,
  *         db.gas_meter,
  *         &mut used_gas as *mut u64,
@@ -253,7 +254,7 @@ typedef struct iterator_t {
   uint64_t iterator_index;
 } iterator_t;
 
-typedef struct Iterator_vtable {
+typedef struct IteratorVtable {
   int32_t (*next)(struct iterator_t,
                   struct gas_meter_t*,
                   uint64_t*,
@@ -270,15 +271,15 @@ typedef struct Iterator_vtable {
                         uint64_t*,
                         struct UnmanagedVector*,
                         struct UnmanagedVector*);
-} Iterator_vtable;
+} IteratorVtable;
 
 typedef struct GoIter {
   struct gas_meter_t *gas_meter;
   struct iterator_t state;
-  struct Iterator_vtable vtable;
+  struct IteratorVtable vtable;
 } GoIter;
 
-typedef struct Db_vtable {
+typedef struct DbVtable {
   int32_t (*read_db)(struct db_t*,
                      struct gas_meter_t*,
                      uint64_t*,
@@ -304,19 +305,19 @@ typedef struct Db_vtable {
                      int32_t,
                      struct GoIter*,
                      struct UnmanagedVector*);
-} Db_vtable;
+} DbVtable;
 
 typedef struct Db {
   struct gas_meter_t *gas_meter;
   struct db_t *state;
-  struct Db_vtable vtable;
+  struct DbVtable vtable;
 } Db;
 
 typedef struct api_t {
   uint8_t _private[0];
 } api_t;
 
-typedef struct GoApi_vtable {
+typedef struct GoApiVtable {
   int32_t (*humanize_address)(const struct api_t*,
                               struct U8SliceView,
                               struct UnmanagedVector*,
@@ -327,29 +328,29 @@ typedef struct GoApi_vtable {
                                   struct UnmanagedVector*,
                                   struct UnmanagedVector*,
                                   uint64_t*);
-} GoApi_vtable;
+} GoApiVtable;
 
 typedef struct GoApi {
   const struct api_t *state;
-  struct GoApi_vtable vtable;
+  struct GoApiVtable vtable;
 } GoApi;
 
 typedef struct querier_t {
   uint8_t _private[0];
 } querier_t;
 
-typedef struct Querier_vtable {
+typedef struct QuerierVtable {
   int32_t (*query_external)(const struct querier_t*,
                             uint64_t,
                             uint64_t*,
                             struct U8SliceView,
                             struct UnmanagedVector*,
                             struct UnmanagedVector*);
-} Querier_vtable;
+} QuerierVtable;
 
 typedef struct GoQuerier {
   const struct querier_t *state;
-  struct Querier_vtable vtable;
+  struct QuerierVtable vtable;
 } GoQuerier;
 
 typedef struct GasReport {
diff --git a/internal/api/callbacks.go b/internal/api/callbacks.go
index 2f945dfbc..dc5db74b4 100644
--- a/internal/api/callbacks.go
+++ b/internal/api/callbacks.go
@@ -89,7 +89,7 @@ func recoverPanic(ret *C.GoError) {
 
 /****** DB ********/
 
-var db_vtable = C.Db_vtable{
+var db_vtable = C.DbVtable{
 	read_db:   C.any_function_t(C.cGet_cgo),
 	write_db:  C.any_function_t(C.cSet_cgo),
 	remove_db: C.any_function_t(C.cDelete_cgo),
@@ -124,7 +124,7 @@ func buildDB(state *DBState, gm *types.GasMeter) C.Db {
 	}
 }
 
-var iterator_vtable = C.Iterator_vtable{
+var iterator_vtable = C.IteratorVtable{
 	next:       C.any_function_t(C.cNext_cgo),
 	next_key:   C.any_function_t(C.cNextKey_cgo),
 	next_value: C.any_function_t(C.cNextValue_cgo),
@@ -358,7 +358,7 @@ func nextPart(ref C.iterator_t, gasMeter *C.gas_meter_t, usedGas *cu64, output *
 	return C.GoError_None
 }
 
-var api_vtable = C.GoApi_vtable{
+var api_vtable = C.GoApiVtable{
 	humanize_address:     C.any_function_t(C.cHumanAddress_cgo),
 	canonicalize_address: C.any_function_t(C.cCanonicalAddress_cgo),
 }
@@ -429,7 +429,7 @@ func cCanonicalAddress(ptr *C.api_t, src C.U8SliceView, dest *C.UnmanagedVector,
 
 /****** Go Querier ********/
 
-var querier_vtable = C.Querier_vtable{
+var querier_vtable = C.QuerierVtable{
 	query_external: C.any_function_t(C.cQueryExternal_cgo),
 }
 
diff --git a/libwasmvm/bindings.h b/libwasmvm/bindings.h
index 6bb960b4d..bf03c9e24 100644
--- a/libwasmvm/bindings.h
+++ b/libwasmvm/bindings.h
@@ -139,8 +139,9 @@ typedef struct ByteSliceView {
  *     // …
  *     # let mut error_msg = UnmanagedVector::default();
  *     # let mut used_gas = 0_u64;
+ *     # let read_db = db.vtable.read_db.unwrap();
  *
- *     let go_error: GoError = (db.vtable.read_db)(
+ *     let go_error: GoError = read_db(
  *         db.state,
  *         db.gas_meter,
  *         &mut used_gas as *mut u64,
@@ -253,7 +254,7 @@ typedef struct iterator_t {
   uint64_t iterator_index;
 } iterator_t;
 
-typedef struct Iterator_vtable {
+typedef struct IteratorVtable {
   int32_t (*next)(struct iterator_t,
                   struct gas_meter_t*,
                   uint64_t*,
@@ -270,15 +271,15 @@ typedef struct Iterator_vtable {
                         uint64_t*,
                         struct UnmanagedVector*,
                         struct UnmanagedVector*);
-} Iterator_vtable;
+} IteratorVtable;
 
 typedef struct GoIter {
   struct gas_meter_t *gas_meter;
   struct iterator_t state;
-  struct Iterator_vtable vtable;
+  struct IteratorVtable vtable;
 } GoIter;
 
-typedef struct Db_vtable {
+typedef struct DbVtable {
   int32_t (*read_db)(struct db_t*,
                      struct gas_meter_t*,
                      uint64_t*,
@@ -304,19 +305,19 @@ typedef struct Db_vtable {
                      int32_t,
                      struct GoIter*,
                      struct UnmanagedVector*);
-} Db_vtable;
+} DbVtable;
 
 typedef struct Db {
   struct gas_meter_t *gas_meter;
   struct db_t *state;
-  struct Db_vtable vtable;
+  struct DbVtable vtable;
 } Db;
 
 typedef struct api_t {
   uint8_t _private[0];
 } api_t;
 
-typedef struct GoApi_vtable {
+typedef struct GoApiVtable {
   int32_t (*humanize_address)(const struct api_t*,
                               struct U8SliceView,
                               struct UnmanagedVector*,
@@ -327,29 +328,29 @@ typedef struct GoApi_vtable {
                                   struct UnmanagedVector*,
                                   struct UnmanagedVector*,
                                   uint64_t*);
-} GoApi_vtable;
+} GoApiVtable;
 
 typedef struct GoApi {
   const struct api_t *state;
-  struct GoApi_vtable vtable;
+  struct GoApiVtable vtable;
 } GoApi;
 
 typedef struct querier_t {
   uint8_t _private[0];
 } querier_t;
 
-typedef struct Querier_vtable {
+typedef struct QuerierVtable {
   int32_t (*query_external)(const struct querier_t*,
                             uint64_t,
                             uint64_t*,
                             struct U8SliceView,
                             struct UnmanagedVector*,
                             struct UnmanagedVector*);
-} Querier_vtable;
+} QuerierVtable;
 
 typedef struct GoQuerier {
   const struct querier_t *state;
-  struct Querier_vtable vtable;
+  struct QuerierVtable vtable;
 } GoQuerier;
 
 typedef struct GasReport {
diff --git a/libwasmvm/src/api.rs b/libwasmvm/src/api.rs
index e62f39fe1..b1784d8e0 100644
--- a/libwasmvm/src/api.rs
+++ b/libwasmvm/src/api.rs
@@ -2,6 +2,7 @@ use cosmwasm_vm::{BackendApi, BackendError, BackendResult, GasInfo};
 
 use crate::error::GoError;
 use crate::memory::{U8SliceView, UnmanagedVector};
+use crate::Vtable;
 
 // this represents something passed in from the caller side of FFI
 // in this case a struct with go function pointers
@@ -13,29 +14,35 @@ pub struct api_t {
 // These functions should return GoError but because we don't trust them here, we treat the return value as i32
 // and then check it when converting to GoError manually
 #[repr(C)]
-#[derive(Copy, Clone)]
-pub struct GoApi_vtable {
-    pub humanize_address: extern "C" fn(
-        *const api_t,
-        U8SliceView,
-        *mut UnmanagedVector, // human output
-        *mut UnmanagedVector, // error message output
-        *mut u64,
-    ) -> i32,
-    pub canonicalize_address: extern "C" fn(
-        *const api_t,
-        U8SliceView,
-        *mut UnmanagedVector, // canonical output
-        *mut UnmanagedVector, // error message output
-        *mut u64,
-    ) -> i32,
+#[derive(Copy, Clone, Default)]
+pub struct GoApiVtable {
+    pub humanize_address: Option<
+        extern "C" fn(
+            *const api_t,
+            U8SliceView,
+            *mut UnmanagedVector, // human output
+            *mut UnmanagedVector, // error message output
+            *mut u64,
+        ) -> i32,
+    >,
+    pub canonicalize_address: Option<
+        extern "C" fn(
+            *const api_t,
+            U8SliceView,
+            *mut UnmanagedVector, // canonical output
+            *mut UnmanagedVector, // error message output
+            *mut u64,
+        ) -> i32,
+    >,
 }
 
+impl Vtable for GoApiVtable {}
+
 #[repr(C)]
 #[derive(Copy, Clone)]
 pub struct GoApi {
     pub state: *const api_t,
-    pub vtable: GoApi_vtable,
+    pub vtable: GoApiVtable,
 }
 
 // We must declare that these are safe to Send, to use in wasm.
@@ -50,7 +57,11 @@ impl BackendApi for GoApi {
         let mut output = UnmanagedVector::default();
         let mut error_msg = UnmanagedVector::default();
         let mut used_gas = 0_u64;
-        let go_error: GoError = (self.vtable.canonicalize_address)(
+        let canonicalize_address = self
+            .vtable
+            .canonicalize_address
+            .expect("vtable function 'canonicalize_address' not set");
+        let go_error: GoError = canonicalize_address(
             self.state,
             U8SliceView::new(Some(human.as_bytes())),
             &mut output as *mut UnmanagedVector,
@@ -79,7 +90,11 @@ impl BackendApi for GoApi {
         let mut output = UnmanagedVector::default();
         let mut error_msg = UnmanagedVector::default();
         let mut used_gas = 0_u64;
-        let go_error: GoError = (self.vtable.humanize_address)(
+        let humanize_address = self
+            .vtable
+            .humanize_address
+            .expect("vtable function 'humanize_address' not set");
+        let go_error: GoError = humanize_address(
             self.state,
             U8SliceView::new(Some(canonical)),
             &mut output as *mut UnmanagedVector,
diff --git a/libwasmvm/src/db.rs b/libwasmvm/src/db.rs
index c34fec57f..f762c92ed 100644
--- a/libwasmvm/src/db.rs
+++ b/libwasmvm/src/db.rs
@@ -1,6 +1,7 @@
 use crate::gas_meter::gas_meter_t;
 use crate::iterator::GoIter;
 use crate::memory::{U8SliceView, UnmanagedVector};
+use crate::vtables::Vtable;
 
 // this represents something passed in from the caller side of FFI
 #[repr(C)]
@@ -11,48 +12,59 @@ pub struct db_t {
 // These functions should return GoError but because we don't trust them here, we treat the return value as i32
 // and then check it when converting to GoError manually
 #[repr(C)]
-pub struct Db_vtable {
-    pub read_db: extern "C" fn(
-        *mut db_t,
-        *mut gas_meter_t,
-        *mut u64,
-        U8SliceView,
-        *mut UnmanagedVector, // result output
-        *mut UnmanagedVector, // error message output
-    ) -> i32,
-    pub write_db: extern "C" fn(
-        *mut db_t,
-        *mut gas_meter_t,
-        *mut u64,
-        U8SliceView,
-        U8SliceView,
-        *mut UnmanagedVector, // error message output
-    ) -> i32,
-    pub remove_db: extern "C" fn(
-        *mut db_t,
-        *mut gas_meter_t,
-        *mut u64,
-        U8SliceView,
-        *mut UnmanagedVector, // error message output
-    ) -> i32,
+#[derive(Default)]
+pub struct DbVtable {
+    pub read_db: Option<
+        extern "C" fn(
+            *mut db_t,
+            *mut gas_meter_t,
+            *mut u64,
+            U8SliceView,
+            *mut UnmanagedVector, // result output
+            *mut UnmanagedVector, // error message output
+        ) -> i32,
+    >,
+    pub write_db: Option<
+        extern "C" fn(
+            *mut db_t,
+            *mut gas_meter_t,
+            *mut u64,
+            U8SliceView,
+            U8SliceView,
+            *mut UnmanagedVector, // error message output
+        ) -> i32,
+    >,
+    pub remove_db: Option<
+        extern "C" fn(
+            *mut db_t,
+            *mut gas_meter_t,
+            *mut u64,
+            U8SliceView,
+            *mut UnmanagedVector, // error message output
+        ) -> i32,
+    >,
     // order -> Ascending = 1, Descending = 2
     // Note: we cannot set gas_meter on the returned GoIter due to cgo memory safety.
     // Since we have the pointer in rust already, we must set that manually
-    pub scan_db: extern "C" fn(
-        *mut db_t,
-        *mut gas_meter_t,
-        *mut u64,
-        U8SliceView,
-        U8SliceView,
-        i32,
-        *mut GoIter,
-        *mut UnmanagedVector, // error message output
-    ) -> i32,
+    pub scan_db: Option<
+        extern "C" fn(
+            *mut db_t,
+            *mut gas_meter_t,
+            *mut u64,
+            U8SliceView,
+            U8SliceView,
+            i32,
+            *mut GoIter,
+            *mut UnmanagedVector, // error message output
+        ) -> i32,
+    >,
 }
 
+impl Vtable for DbVtable {}
+
 #[repr(C)]
 pub struct Db {
     pub gas_meter: *mut gas_meter_t,
     pub state: *mut db_t,
-    pub vtable: Db_vtable,
+    pub vtable: DbVtable,
 }
diff --git a/libwasmvm/src/iterator.rs b/libwasmvm/src/iterator.rs
index 00b350e29..7f8de7729 100644
--- a/libwasmvm/src/iterator.rs
+++ b/libwasmvm/src/iterator.rs
@@ -4,6 +4,7 @@ use cosmwasm_vm::{BackendError, BackendResult, GasInfo};
 use crate::error::GoError;
 use crate::gas_meter::gas_meter_t;
 use crate::memory::UnmanagedVector;
+use crate::vtables::Vtable;
 
 // Iterator maintains integer references to some tables on the Go side
 #[repr(C)]
@@ -18,7 +19,7 @@ pub struct iterator_t {
 // and then check it when converting to GoError manually
 #[repr(C)]
 #[derive(Default)]
-pub struct Iterator_vtable {
+pub struct IteratorVtable {
     pub next: Option<
         extern "C" fn(
             iterator_t,
@@ -49,11 +50,13 @@ pub struct Iterator_vtable {
     >,
 }
 
+impl Vtable for IteratorVtable {}
+
 #[repr(C)]
 pub struct GoIter {
     pub gas_meter: *mut gas_meter_t,
     pub state: iterator_t,
-    pub vtable: Iterator_vtable,
+    pub vtable: IteratorVtable,
 }
 
 impl GoIter {
@@ -61,17 +64,15 @@ impl GoIter {
         GoIter {
             gas_meter,
             state: iterator_t::default(),
-            vtable: Iterator_vtable::default(),
+            vtable: IteratorVtable::default(),
         }
     }
 
     pub fn next(&mut self) -> BackendResult<Option<Record>> {
-        let Some(next) = self.vtable.next else {
-            let result = Err(BackendError::unknown(
-                "iterator vtable function 'next' not set",
-            ));
-            return (result, GasInfo::free());
-        };
+        let next = self
+            .vtable
+            .next
+            .expect("iterator vtable function 'next' not set");
 
         let mut output_key = UnmanagedVector::default();
         let mut output_value = UnmanagedVector::default();
@@ -116,22 +117,18 @@ impl GoIter {
     }
 
     pub fn next_key(&mut self) -> BackendResult<Option<Vec<u8>>> {
-        let Some(next_key) = self.vtable.next_key else {
-            let result = Err(BackendError::unknown(
-                "iterator vtable function 'next_key' not set",
-            ));
-            return (result, GasInfo::free());
-        };
+        let next_key = self
+            .vtable
+            .next_key
+            .expect("iterator vtable function 'next_key' not set");
         self.next_key_or_val(next_key)
     }
 
     pub fn next_value(&mut self) -> BackendResult<Option<Vec<u8>>> {
-        let Some(next_value) = self.vtable.next_value else {
-            let result = Err(BackendError::unknown(
-                "iterator vtable function 'next_value' not set",
-            ));
-            return (result, GasInfo::free());
-        };
+        let next_value = self
+            .vtable
+            .next_value
+            .expect("iterator vtable function 'next_value' not set");
         self.next_key_or_val(next_value)
     }
 
diff --git a/libwasmvm/src/lib.rs b/libwasmvm/src/lib.rs
index 2e431fe30..8edf84e20 100644
--- a/libwasmvm/src/lib.rs
+++ b/libwasmvm/src/lib.rs
@@ -16,17 +16,20 @@ mod storage;
 mod test_utils;
 mod tests;
 mod version;
+mod vtables;
 
 // We only interact with this crate via `extern "C"` interfaces, not those public
 // exports. There are no guarantees those exports are stable.
 // We keep them here such that we can access them in the docs (`cargo doc`).
-pub use api::GoApi;
+pub use api::{GoApi, GoApiVtable};
 pub use cache::{cache_t, load_wasm};
-pub use db::{db_t, Db};
+pub use db::{db_t, Db, DbVtable};
 pub use error::GoError;
 pub use gas_report::GasReport;
+pub use iterator::IteratorVtable;
 pub use memory::{
     destroy_unmanaged_vector, new_unmanaged_vector, ByteSliceView, U8SliceView, UnmanagedVector,
 };
-pub use querier::GoQuerier;
+pub use querier::{GoQuerier, QuerierVtable};
 pub use storage::GoStorage;
+pub use vtables::Vtable;
diff --git a/libwasmvm/src/memory.rs b/libwasmvm/src/memory.rs
index 24d6e91b8..7df702249 100644
--- a/libwasmvm/src/memory.rs
+++ b/libwasmvm/src/memory.rs
@@ -156,8 +156,9 @@ impl U8SliceView {
 ///     // …
 ///     # let mut error_msg = UnmanagedVector::default();
 ///     # let mut used_gas = 0_u64;
+///     # let read_db = db.vtable.read_db.unwrap();
 ///
-///     let go_error: GoError = (db.vtable.read_db)(
+///     let go_error: GoError = read_db(
 ///         db.state,
 ///         db.gas_meter,
 ///         &mut used_gas as *mut u64,
diff --git a/libwasmvm/src/querier.rs b/libwasmvm/src/querier.rs
index 3d22a48a7..ba40faabf 100644
--- a/libwasmvm/src/querier.rs
+++ b/libwasmvm/src/querier.rs
@@ -3,6 +3,7 @@ use cosmwasm_vm::{BackendResult, GasInfo, Querier};
 
 use crate::error::GoError;
 use crate::memory::{U8SliceView, UnmanagedVector};
+use crate::Vtable;
 
 // this represents something passed in from the caller side of FFI
 #[repr(C)]
@@ -12,24 +13,28 @@ pub struct querier_t {
 }
 
 #[repr(C)]
-#[derive(Clone)]
-pub struct Querier_vtable {
+#[derive(Clone, Default)]
+pub struct QuerierVtable {
     // We return errors through the return buffer, but may return non-zero error codes on panic
-    pub query_external: extern "C" fn(
-        *const querier_t,
-        u64,
-        *mut u64,
-        U8SliceView,
-        *mut UnmanagedVector, // result output
-        *mut UnmanagedVector, // error message output
-    ) -> i32,
+    pub query_external: Option<
+        extern "C" fn(
+            *const querier_t,
+            u64,
+            *mut u64,
+            U8SliceView,
+            *mut UnmanagedVector, // result output
+            *mut UnmanagedVector, // error message output
+        ) -> i32,
+    >,
 }
 
+impl Vtable for QuerierVtable {}
+
 #[repr(C)]
 #[derive(Clone)]
 pub struct GoQuerier {
     pub state: *const querier_t,
-    pub vtable: Querier_vtable,
+    pub vtable: QuerierVtable,
 }
 
 // TODO: check if we can do this safer...
@@ -44,7 +49,11 @@ impl Querier for GoQuerier {
         let mut output = UnmanagedVector::default();
         let mut error_msg = UnmanagedVector::default();
         let mut used_gas = 0_u64;
-        let go_result: GoError = (self.vtable.query_external)(
+        let query_external = self
+            .vtable
+            .query_external
+            .expect("vtable function 'query_external' not set");
+        let go_result: GoError = query_external(
             self.state,
             gas_limit,
             &mut used_gas as *mut u64,
diff --git a/libwasmvm/src/storage.rs b/libwasmvm/src/storage.rs
index fc7a75046..0a22061dd 100644
--- a/libwasmvm/src/storage.rs
+++ b/libwasmvm/src/storage.rs
@@ -28,7 +28,12 @@ impl Storage for GoStorage {
         let mut output = UnmanagedVector::default();
         let mut error_msg = UnmanagedVector::default();
         let mut used_gas = 0_u64;
-        let go_error: GoError = (self.db.vtable.read_db)(
+        let read_db = self
+            .db
+            .vtable
+            .read_db
+            .expect("vtable function 'read_db' not set");
+        let go_error: GoError = read_db(
             self.db.state,
             self.db.gas_meter,
             &mut used_gas as *mut u64,
@@ -67,7 +72,12 @@ impl Storage for GoStorage {
         let mut error_msg = UnmanagedVector::default();
         let mut iter = GoIter::new(self.db.gas_meter);
         let mut used_gas = 0_u64;
-        let go_error: GoError = (self.db.vtable.scan_db)(
+        let scan_db = self
+            .db
+            .vtable
+            .scan_db
+            .expect("vtable function 'scan_db' not set");
+        let go_error: GoError = scan_db(
             self.db.state,
             self.db.gas_meter,
             &mut used_gas as *mut u64,
@@ -138,7 +148,12 @@ impl Storage for GoStorage {
     fn set(&mut self, key: &[u8], value: &[u8]) -> BackendResult<()> {
         let mut error_msg = UnmanagedVector::default();
         let mut used_gas = 0_u64;
-        let go_error: GoError = (self.db.vtable.write_db)(
+        let write_db = self
+            .db
+            .vtable
+            .write_db
+            .expect("vtable function 'write_db' not set");
+        let go_error: GoError = write_db(
             self.db.state,
             self.db.gas_meter,
             &mut used_gas as *mut u64,
@@ -166,7 +181,12 @@ impl Storage for GoStorage {
     fn remove(&mut self, key: &[u8]) -> BackendResult<()> {
         let mut error_msg = UnmanagedVector::default();
         let mut used_gas = 0_u64;
-        let go_error: GoError = (self.db.vtable.remove_db)(
+        let remove_db = self
+            .db
+            .vtable
+            .remove_db
+            .expect("vtable function 'remove_db' not set");
+        let go_error: GoError = remove_db(
             self.db.state,
             self.db.gas_meter,
             &mut used_gas as *mut u64,
diff --git a/libwasmvm/src/vtables.rs b/libwasmvm/src/vtables.rs
new file mode 100644
index 000000000..642021874
--- /dev/null
+++ b/libwasmvm/src/vtables.rs
@@ -0,0 +1,46 @@
+/// Vtables are a collection of free function. Those functions are created in Go and
+/// then assigned via function pointers that Rust can call. The functions do not
+/// change during the lifetime of the object.
+///
+/// Since the functions are free, a single function is used for multiple instances.
+/// In fact, in Go we create a single global vtable variable holding and owning the
+/// function the vtables in Rust point to.
+///
+/// The `Vtable` trait is created to find those vtables troughout the codebase.
+///
+/// ## Nullability
+///
+/// Since all functions are represented as a function pointer, they are naturally
+/// nullable. I.e. in Go we can always set them to `nil`. For this reason the functions
+/// are all wrapped in Options, e.g.
+///
+/// ```
+/// # use wasmvm::UnmanagedVector;
+/// # struct iterator_t;
+/// # struct gas_meter_t;
+/// pub struct IteratorVtable {
+///     pub next: Option<
+///         extern "C" fn(
+///             iterator_t,
+///             *mut gas_meter_t,
+///             *mut u64,
+///             *mut UnmanagedVector, // key output
+///             *mut UnmanagedVector, // value output
+///             *mut UnmanagedVector, // error message output
+///         ) -> i32,
+///     >,
+///     // ...
+/// }
+/// ```
+///
+/// Or to say it in the words of [the Rust documentation](https://doc.rust-lang.org/nomicon/ffi.html#the-nullable-pointer-optimization):
+///
+/// > So `Option<extern "C" fn(c_int) -> c_int>` is a correct way to represent a nullable function pointer using the C ABI (corresponding to the C type `int (*)(int))`.
+///
+/// Since all vtable fields are nullable, we can easily demand them
+/// to have a Default implementation. This sometimes is handy when a
+/// type is created in Rust and then filled in Go.
+///
+/// Missing vtable fields always indicate a lifecycle bug in wasmvm and
+/// should be treated with a panic.
+pub trait Vtable: Default {}