opti test and add javadoc

Author: hqbfzwang

pulsar-broker/src/test/java/org/apache/pulsar/client/impl/MessageChecksumTest.java

@@ -38,7 +38,7 @@
 import org.apache.pulsar.client.api.PulsarClientException;
 import org.apache.pulsar.client.api.TypedMessageBuilder;
 import org.apache.pulsar.client.impl.ProducerImpl.OpSendMsg;
-import org.apache.pulsar.client.impl.metrics.LatencyHistogram;
+import org.apache.pulsar.client.impl.metrics.ProducerMetrics;
 import org.apache.pulsar.common.api.proto.MessageMetadata;
 import org.apache.pulsar.common.api.proto.ProtocolVersion;
 import org.apache.pulsar.common.protocol.ByteBufPair;
@@ -238,7 +238,7 @@ public void testTamperingMessageIsDetected() throws Exception {
         // WHEN
         // protocol message is created with checksum
         ByteBufPair cmd = Commands.newSend(1, 1, 1, ChecksumType.Crc32c, msgMetadata, payload);
-        OpSendMsg op = OpSendMsg.create(LatencyHistogram.NOOP,
+        OpSendMsg op = OpSendMsg.create(ProducerMetrics.NOOP,
                 (MessageImpl<byte[]>) msgBuilder.getMessage(), cmd, 1, null);
 
         // THEN

pulsar-broker/src/test/java/org/apache/pulsar/client/impl/MessageChunkingTest.java

@@ -56,7 +56,7 @@
 import org.apache.pulsar.client.api.SizeUnit;
 import org.apache.pulsar.client.impl.MessageImpl.SchemaState;
 import org.apache.pulsar.client.impl.ProducerImpl.OpSendMsg;
-import org.apache.pulsar.client.impl.metrics.LatencyHistogram;
+import org.apache.pulsar.client.impl.metrics.ProducerMetrics;
 import org.apache.pulsar.common.api.proto.MessageMetadata;
 import org.apache.pulsar.common.policies.data.PublisherStats;
 import org.apache.pulsar.common.protocol.ByteBufPair;
@@ -464,7 +464,7 @@ public void testExpireIncompleteChunkMessage() throws Exception{
         ByteBufPair cmd = Commands.newSend(producerId, 1, 1, ChecksumType.Crc32c, msgMetadata, payload);
         MessageImpl msgImpl = ((MessageImpl<byte[]>) msg.getMessage());
         msgImpl.setSchemaState(SchemaState.Ready);
-        OpSendMsg op = OpSendMsg.create(LatencyHistogram.NOOP, msgImpl, cmd, 1, null);
+        OpSendMsg op = OpSendMsg.create(ProducerMetrics.NOOP, msgImpl, cmd, 1, null);
         producer.processOpSendMsg(op);
 
         retryStrategically((test) -> {

pulsar-client/src/main/java/org/apache/pulsar/client/impl/metrics/ProducerMetrics.java

@@ -27,6 +27,9 @@
  */
 public class ProducerMetrics {
 
+    // Used for tests
+    public static final ProducerMetrics NOOP = new ProducerMetrics(InstrumentProvider.NOOP, null);
+
     private final LatencyHistogram sendLatencyHistogram;
     private final LatencyHistogram rpcLatencyHistogram;
     private final Counter publishedBytesCounter;