fix(sdk): fix incorrect doc (#1499)

Co-authored-by: Cijo Thomas <[email protected]>

opentelemetry-sdk/src/metrics/meter_provider.rs

@@ -38,10 +38,7 @@ impl Default for SdkMeterProvider {
 }
 
 impl SdkMeterProvider {
-    /// Flushes all pending telemetry.
-    ///
-    /// There is no guaranteed that all telemetry be flushed or all resources have
-    /// been released on error.
+    /// Return default [MeterProviderBuilder]
     pub fn builder() -> MeterProviderBuilder {
         MeterProviderBuilder::default()
     }

opentelemetry-sdk/src/propagation/baggage.rs

@@ -1,45 +1,3 @@
-//! # OpenTelemetry Baggage API
-//!
-//! Baggage is used to annotate telemetry, adding context and
-//! information to metrics, traces, and logs. It is an abstract data type
-//! represented by a set of name-value pairs describing user-defined properties.
-//! Each name in a [`Baggage`] is associated with exactly one value.
-//! `Baggage`s are serialized according to the editor's draft of
-//! the [W3C Baggage] specification.
-//!
-//! [`Baggage`]: opentelemetry::baggage::Baggage
-//! [W3C Baggage]: https://w3c.github.io/baggage/
-//!
-//! # Examples
-//!
-//! ```
-//! use opentelemetry::{baggage::BaggageExt, Key, propagation::TextMapPropagator};
-//! use opentelemetry_sdk::propagation::BaggagePropagator;
-//! use std::collections::HashMap;
-//!
-//! // Example baggage value passed in externally via http headers
-//! let mut headers = HashMap::new();
-//! headers.insert("baggage".to_string(), "user_id=1".to_string());
-//!
-//! let propagator = BaggagePropagator::new();
-//! // can extract from any type that impls `Extractor`, usually an HTTP header map
-//! let cx = propagator.extract(&headers);
-//!
-//! // Iterate over extracted name-value pairs
-//! for (name, value) in cx.baggage() {
-//!     // ...
-//! }
-//!
-//! // Add new baggage
-//! let cx_with_additions = cx.with_baggage(vec![Key::new("server_id").i64(42)]);
-//!
-//! // Inject baggage into http request
-//! propagator.inject_context(&cx_with_additions, &mut headers);
-//!
-//! let header_value = headers.get("baggage").expect("header is injected");
-//! assert!(header_value.contains("user_id=1"), "still contains previous name-value");
-//! assert!(header_value.contains("server_id=42"), "contains new name-value pair");
-//! ```
 use once_cell::sync::Lazy;
 use opentelemetry::{
     baggage::{BaggageExt, KeyValueMetadata},

opentelemetry-sdk/src/propagation/trace_context.rs

@@ -1,22 +1,6 @@
 //! # W3C Trace Context Propagator
 //!
-//! The `traceparent` header represents the incoming request in a
-//! tracing system in a common format, understood by all vendors.
-//! Here’s an example of a `traceparent` header.
-//!
-//! `traceparent: 00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01`
-//!
-//! The `traceparent` HTTP header field identifies the incoming request in a
-//! tracing system. It has four fields:
-//!
-//!    - version
-//!    - trace-id
-//!    - parent-id
-//!    - trace-flags
-//!
-//! See the [w3c trace-context docs] for more details.
-//!
-//! [w3c trace-context docs]: https://w3c.github.io/trace-context/
+
 use once_cell::sync::Lazy;
 use opentelemetry::{
     propagation::{text_map_propagator::FieldIter, Extractor, Injector, TextMapPropagator},
@@ -33,8 +17,31 @@ const TRACESTATE_HEADER: &str = "tracestate";
 static TRACE_CONTEXT_HEADER_FIELDS: Lazy<[String; 2]> =
     Lazy::new(|| [TRACEPARENT_HEADER.to_owned(), TRACESTATE_HEADER.to_owned()]);
 
-/// Propagates `SpanContext`s in [W3C TraceContext] format.
+/// Propagates `SpanContext`s in [W3C TraceContext] format under `traceparent` and `tracestate` header.
+///
+/// The `traceparent` header represents the incoming request in a
+/// tracing system in a common format, understood by all vendors.
+/// Here’s an example of a `traceparent` header.
+///
+/// `traceparent: 00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01`
+///
+/// The `traceparent` HTTP header field identifies the incoming request in a
+/// tracing system. It has four fields:
+///
+///    - version
+///    - trace-id
+///    - parent-id
+///    - trace-flags
+///
+/// The `tracestate` header provides additional vendor-specific trace
+/// identification information across different distributed tracing systems.
+/// Here's an example of a `tracestate` header
+///
+/// `tracestate: vendorname1=opaqueValue1,vendorname2=opaqueValue2`
+///
+/// See the [w3c trace-context docs] for more details.
 ///
+/// [w3c trace-context docs]: https://w3c.github.io/trace-context/
 /// [W3C TraceContext]: https://www.w3.org/TR/trace-context/
 #[derive(Clone, Debug, Default)]
 pub struct TraceContextPropagator {