address review 2

Author: alexbrt

opentelemetry-sdk/CHANGELOG.md

@@ -4,6 +4,7 @@
 
 - TODO: Placeholder for Span processor related things
   - *Fix* SpanProcessor::on_start is no longer called on non recording spans
+- **Fix**: Restore true parallel exports in the async-native `BatchSpanProcessor` by honoring `OTEL_BSP_MAX_CONCURRENT_EXPORTS` ([#2959](https://github.com/open-telemetry/opentelemetry-rust/pull/3028)). A regression in [#2685](https://github.com/open-telemetry/opentelemetry-rust/pull/2685) inadvertently awaited the `export()` future directly in `opentelemetry-sdk/src/trace/span_processor_with_async_runtime.rs` instead of spawning it on the runtime, forcing all exports to run sequentially.
 
 ## 0.30.0
 

opentelemetry-sdk/src/trace/span_processor_with_async_runtime.rs

@@ -190,8 +190,11 @@ struct BatchSpanProcessorInternal<E, R> {
     spans: Vec<SpanData>,
     export_tasks: FuturesUnordered<BoxFuture<'static, OTelSdkResult>>,
     runtime: R,
-    exporter: Arc<RwLock<E>>,
     config: BatchConfig,
+    // TODO: Redesign the `SpanExporter` trait to use immutable references (`&self`)
+    // for all methods. This would allow us to remove the `RwLock` and just use `Arc<E>`,
+    // similar to how `crate::logs::LogExporter` is implemented.
+    exporter: Arc<RwLock<E>>,
 }
 
 impl<E: SpanExporter + 'static, R: RuntimeChannel> BatchSpanProcessorInternal<E, R> {