Minor: Add doc example to RecordBatchStreamAdapter (#13725)

* Minor: Add doc example to RecordBatchStreamAdapter

* Update datafusion/physical-plan/src/stream.rs

Co-authored-by: Berkay Şahin <124376117+berkaysynnada@users.noreply.github.com>

---------

Co-authored-by: Berkay Şahin <124376117+berkaysynnada@users.noreply.github.com>

Author: alamb

datafusion/physical-plan/src/stream.rs

@@ -337,7 +337,9 @@ impl RecordBatchReceiverStream {
 
 pin_project! {
     /// Combines a [`Stream`] with a [`SchemaRef`] implementing
-    /// [`RecordBatchStream`] for the combination
+    /// [`SendableRecordBatchStream`] for the combination
+    ///
+    /// See [`Self::new`] for an example
     pub struct RecordBatchStreamAdapter<S> {
         schema: SchemaRef,
 
@@ -347,7 +349,28 @@ pin_project! {
 }
 
 impl<S> RecordBatchStreamAdapter<S> {
-    /// Creates a new [`RecordBatchStreamAdapter`] from the provided schema and stream
+    /// Creates a new [`RecordBatchStreamAdapter`] from the provided schema and stream.
+    ///
+    /// Note to create a [`SendableRecordBatchStream`] you pin the result
+    ///
+    /// # Example
+    /// ```
+    /// # use arrow::array::record_batch;
+    /// # use datafusion_execution::SendableRecordBatchStream;
+    /// # use datafusion_physical_plan::stream::RecordBatchStreamAdapter;
+    /// // Create stream of Result<RecordBatch>
+    /// let batch = record_batch!(
+    ///   ("a", Int32, [1, 2, 3]),
+    ///   ("b", Float64, [Some(4.0), None, Some(5.0)])
+    /// ).expect("created batch");
+    /// let schema = batch.schema();
+    /// let stream = futures::stream::iter(vec![Ok(batch)]);
+    /// // Convert the stream to a SendableRecordBatchStream
+    /// let adapter = RecordBatchStreamAdapter::new(schema, stream);
+    /// // Now you can use the adapter as a SendableRecordBatchStream
+    /// let batch_stream: SendableRecordBatchStream = Box::pin(adapter);
+    /// // ...
+    /// ```
     pub fn new(schema: SchemaRef, stream: S) -> Self {
         Self { schema, stream }
     }