Use volatile

core/src/main/java/io/grpc/internal/DelayedClientTransport.java

@@ -38,7 +38,6 @@
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.concurrent.Executor;
-import java.util.concurrent.atomic.AtomicReference;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
@@ -173,11 +172,11 @@ public final ClientStream newStream(
    * schedule tasks on syncContext.
    */
   @GuardedBy("lock")
-  private PendingStream createPendingStream(
-      PickSubchannelArgs args, ClientStreamTracer[] tracers, PickResult pickResult) {
+  private PendingStream createPendingStream(PickSubchannelArgs args, ClientStreamTracer[] tracers,
+      PickResult pickResult) {
     PendingStream pendingStream = new PendingStream(args, tracers);
     if (args.getCallOptions().isWaitForReady() && pickResult != null && pickResult.hasResult()) {
-      pendingStream.lastPickStatus.set(pickResult.getStatus());
+      pendingStream.lastPickStatus = pickResult.getStatus();
     }
     pendingStreams.add(pendingStream);
     if (getPendingStreamsCount() == 1) {
@@ -298,10 +297,8 @@ final void reprocess(@Nullable SubchannelPicker picker) {
     for (final PendingStream stream : toProcess) {
       PickResult pickResult = picker.pickSubchannel(stream.args);
       CallOptions callOptions = stream.args.getCallOptions();
-      synchronized (lock) {
-        if (callOptions.isWaitForReady() && pickResult.hasResult()) {
-          stream.lastPickStatus.set(pickResult.getStatus());
-        }
+      if (callOptions.isWaitForReady() && pickResult.hasResult()) {
+        stream.lastPickStatus = pickResult.getStatus();
       }
       // User code provided authority takes precedence over the LB provided one.
       if (callOptions.getAuthority() == null && pickResult.getAuthorityOverride() != null) {
@@ -363,7 +360,7 @@ private class PendingStream extends DelayedStream {
     private final PickSubchannelArgs args;
     private final Context context = Context.current();
     private final ClientStreamTracer[] tracers;
-    private final AtomicReference<Status> lastPickStatus = new AtomicReference<>(null);
+    private volatile Status lastPickStatus;
 
     private PendingStream(PickSubchannelArgs args, ClientStreamTracer[] tracers) {
       this.args = args;
@@ -420,9 +417,8 @@ protected void onEarlyCancellation(Status reason) {
     public void appendTimeoutInsight(InsightBuilder insight) {
       if (args.getCallOptions().isWaitForReady()) {
         insight.append("wait_for_ready");
-        Status status = lastPickStatus.get();
-        if (status != null && !status.isOk()) {
-          insight.appendKeyValue("Last Pick Failure", status);
+        if (lastPickStatus != null && !lastPickStatus.isOk()) {
+          insight.appendKeyValue("Last Pick Failure", lastPickStatus);
         }
       }
       super.appendTimeoutInsight(insight);