Updates test and optimizes collector scheduler (#3351)

- Test
  - Junit4 4.13.1 -> 4.13.2
  - Mockito 3.6.28 -> 3.8.0

pom.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
 
-    Copyright 2015-2021 The OpenZipkin Authors
+    Copyright 2015-2023 The OpenZipkin Authors
 
     Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
     in compliance with the License. You may obtain a copy of the License at
@@ -85,9 +85,9 @@
     <git-commit-id.version>4.0.3</git-commit-id.version>
 
     <!-- Test only dependencies -->
-    <junit.version>4.13.1</junit.version>
+    <junit.version>4.13.2</junit.version>
     <junit-jupiter.version>5.9.2</junit-jupiter.version>
-    <mockito.version>3.6.28</mockito.version>
+    <mockito.version>3.8.0</mockito.version>
     <assertj.version>3.18.1</assertj.version>
     <awaitility.version>4.0.3</awaitility.version>
     <hamcrest.version>1.3</hamcrest.version>

zipkin-server/src/main/java/zipkin2/server/internal/ZipkinGrpcCollector.java

@@ -58,7 +58,7 @@ static final class SpanService extends AbstractUnsafeUnaryGrpcService {
       this.metrics = metrics;
     }
 
-    @Override protected CompletionStage<ByteBuf> handleMessage(ServiceRequestContext srCtx, ByteBuf bytes) {
+    @Override protected CompletionStage<ByteBuf> handleMessage(ServiceRequestContext ctx, ByteBuf bytes) {
       metrics.incrementMessages();
       metrics.incrementBytes(bytes.readableBytes());
 
@@ -68,15 +68,7 @@ static final class SpanService extends AbstractUnsafeUnaryGrpcService {
 
       try {
         CompletableFutureCallback result = new CompletableFutureCallback();
-
-        // collector.accept might block so need to move off the event loop. We make sure the
-        // callback is context aware to continue the trace.
-        Executor executor = ServiceRequestContext.mapCurrent(
-          ctx -> ctx.makeContextAware(ctx.blockingTaskExecutor()),
-          CommonPools::blockingTaskExecutor);
-
-        collector.acceptSpans(bytes.nioBuffer(), SpanBytesDecoder.PROTO3, result, executor);
-
+        collector.acceptSpans(bytes.nioBuffer(), SpanBytesDecoder.PROTO3, result, ctx.blockingTaskExecutor());
         return result;
       } finally {
         bytes.release();