Add context capture and continued methods.

e2e/data/expected_context.yaml

@@ -16,8 +16,30 @@
 # under the License.
 #
 segmentItems:
-- segmentSize: 1
+- segmentSize: 2
   segments:
+  - segmentId: not null
+    spans:
+    - componentId: 11000
+      endTime: gt 0
+      isError: false
+      operationName: async-callback
+      parentSpanId: -1
+      peer: ''
+      refs:
+      - networkAddress: ''
+        parentEndpoint: async-job
+        parentService: producer
+        parentServiceInstance: node_0
+        parentSpanId: 2
+        parentTraceSegmentId: not null
+        refType: CrossThread
+        traceId: not null
+      skipAnalysis: false
+      spanId: 0
+      spanLayer: Http
+      spanType: Entry
+      startTime: gt 0
   - segmentId: not null
     spans:
     - componentId: 11000
@@ -31,6 +53,17 @@ segmentItems:
       spanLayer: Http
       spanType: Exit
       startTime: gt 0
+    - componentId: 11000
+      endTime: gt 0
+      isError: false
+      operationName: async-job
+      parentSpanId: 0
+      peer: ''
+      skipAnalysis: false
+      spanId: 2
+      spanLayer: Unknown
+      spanType: Local
+      startTime: gt 0
     - componentId: 11000
       endTime: gt 0
       isError: false

e2e/src/main.rs

@@ -50,6 +50,18 @@ async fn handle_ping(
 
         client.request(req).await.unwrap();
     }
+    {
+        let _span3 = context.create_local_span("async-job");
+        let snapshot = context.capture();
+
+        tokio::spawn(async move {
+            let mut context2 = tracer::create_trace_context();
+            let _span3 = context2.create_entry_span("async-callback");
+            context2.continued(snapshot);
+        })
+        .await
+        .unwrap();
+    }
     Ok(Response::new(Body::from("hoge")))
 }