Docs fixes

src/lib.rs

@@ -9,6 +9,8 @@
 //!
 //! ## Trace
 //!
+//! This requires the **trace** feature (enabled by default).
+//!
 //! Configure a OpenTelemetry pipeline using the Application Insights exporter and start creating
 //! spans (this example requires the **opentelemetry-http/reqwest** feature):
 //!
@@ -28,6 +30,8 @@
 //!
 //! ## Logs
 //!
+//! This requires the **logs** feature (enabled by default).
+//!
 //! ```no_run
 //! use log::{Level, info};
 //! use opentelemetry_appender_log::OpenTelemetryLogBridge;
@@ -61,6 +65,8 @@
 //!
 //! ## Metrics
 //!
+//! This requires the **metrics** feature (enabled by default).
+//!
 //! ```no_run
 //! use opentelemetry::global;
 //! use opentelemetry_sdk::metrics::{PeriodicReader, SdkMeterProvider};

src/trace.rs

@@ -127,6 +127,7 @@ impl<C> Exporter<C> {
     }
 }
 
+#[cfg_attr(docsrs, doc(cfg(feature = "trace")))]
 impl<C> SpanExporter for Exporter<C>
 where
     C: HttpClient + 'static,