HDFS-16151. Improve the parameter comments related to ProtobufRpcEngine2#Server(). (#3256)

Co-authored-by: zhujianghua <zhujianghua@zhujianghuadeMacBook-Pro.local>
Reviewed-by: Wei-Chiu Chuang <weichiu@apache.org>
Signed-off-by: Akira Ajisaka <aajisaka@apache.org>

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ipc/ProtobufRpcEngine2.java

@@ -450,7 +450,11 @@ public class ProtobufRpcEngine2 implements RpcEngine {
      * @param bindAddress the address to bind on to listen for connection
      * @param port the port to listen for connections on
      * @param numHandlers the number of method handler threads to run
+     * @param numReaders number of read threads
+     * @param queueSizePerHandler the size of the queue contained
+     *                            in each Handler
      * @param verbose whether each call should be logged
+     * @param secretManager the server-side secret manager for each token type
      * @param portRangeConfig A config parameter that can be used to restrict
      * the range of ports used when port is 0 (an ephemeral port)
      * @param alignmentContext provides server state info on client responses