fix(streamble_http) SendNotification not work bug (#473)

Author: Robin-ZMH

server/streamable_http.go

@@ -293,7 +293,7 @@ func (s *StreamableHTTPServer) handlePost(w http.ResponseWriter, r *http.Request
 						w.Header().Set("Content-Type", "text/event-stream")
 						w.Header().Set("Connection", "keep-alive")
 						w.Header().Set("Cache-Control", "no-cache")
-						w.WriteHeader(http.StatusAccepted)
+						w.WriteHeader(http.StatusOK)
 						upgradedHeader = true
 					}
 					err := writeSSEEvent(w, nt)
@@ -332,7 +332,7 @@ func (s *StreamableHTTPServer) handlePost(w http.ResponseWriter, r *http.Request
 			w.Header().Set("Content-Type", "text/event-stream")
 			w.Header().Set("Connection", "keep-alive")
 			w.Header().Set("Cache-Control", "no-cache")
-			w.WriteHeader(http.StatusAccepted)
+			w.WriteHeader(http.StatusOK)
 			upgradedHeader = true
 		}
 		if err := writeSSEEvent(w, response); err != nil {

server/streamable_http_test.go

@@ -283,8 +283,8 @@ func TestStreamableHTTP_POST_SendAndReceive(t *testing.T) {
 		}
 		defer resp.Body.Close()
 
-		if resp.StatusCode != http.StatusAccepted {
-			t.Errorf("Expected status 202, got %d", resp.StatusCode)
+		if resp.StatusCode != http.StatusOK {
+			t.Errorf("Expected status 200, got %d", resp.StatusCode)
 		}
 		if resp.Header.Get("content-type") != "text/event-stream" {
 			t.Errorf("Expected content-type text/event-stream, got %s", resp.Header.Get("content-type"))