Better zero-copy support for keys and values that can be trivially converted into Slice

[carlsverre]

closes #99
depends on fjall-rs/value-log#11
depends on fjall-rs/lsm-tree#85

[carlsverre]

Tests will fail until fjall-rs/value-log#11 ships. Unless you'd prefer me change the tests.

[marvin-j97]

Into<Slice> should probably be used also in some other places:

https://github.com/fjall-rs/fjall/blob/2d804edf992a600059db96f1b1b2dcc637a50271/src/partition/mod.rs#L857C9-L857C18

fjall/src/partition/mod.rs

Line 920 in 2d804ed

pub fn remove<K: AsRef<[u8]>>(&self, key: K) -> crate::Result<()> {

fjall/src/tx/write/mod.rs

Line 353 in 2d804ed

pub(super) fn insert<K: AsRef<[u8]>, V: AsRef<[u8]>>(

https://github.com/fjall-rs/fjall/blob/2d804edf992a600059db96f1b1b2dcc637a50271/src/tx/write/mod.rs#L379C8-L382C30

fjall/src/tx/write/single_writer.rs

Line 558 in 2d804ed

pub fn insert<K: AsRef<[u8]>, V: AsRef<[u8]>>(

etc. Let me know if you find more...

And actually this may bubble down all the way down to lsm-tree 🥹: https://github.com/fjall-rs/lsm-tree/blob/11479d7a9c24531fb9174c7c3f309735931db4a8/src/abstract.rs#L584C5-L584C14

[carlsverre]

I went through and updated all writing methods to support Into<Slice> on both key and value. I did not change read methods as they mostly just read keys and take references. And Keys are fairly small so the cost is less. To update those methods to take Into<Slice> would require more work in the range conversion code.