[CALCITE-4962] Protobuf debug does not show request/response type
diff --git a/core/src/main/java/org/apache/calcite/avatica/remote/ProtobufTranslationImpl.java b/core/src/main/java/org/apache/calcite/avatica/remote/ProtobufTranslationImpl.java
index eb616a2..7686223 100644
--- a/core/src/main/java/org/apache/calcite/avatica/remote/ProtobufTranslationImpl.java
+++ b/core/src/main/java/org/apache/calcite/avatica/remote/ProtobufTranslationImpl.java
@@ -105,7 +105,11 @@
       // This should already be an aliased CodedInputStream from the WireMessage parsing.
       Message msg = parser.parseFrom(serializedMessage.newCodedInput());
       if (LOG.isTraceEnabled()) {
-        LOG.trace("Deserialized request '{}'", TextFormat.shortDebugString(msg));
+        LOG.trace(
+            "Deserialized {} '{}'",
+            msg.getClass().getSimpleName(),
+            TextFormat.shortDebugString(msg)
+        );
       }
       return impl.deserialize(msg);
     }
@@ -129,7 +133,11 @@
         InvalidProtocolBufferException {
       Message msg = parser.parseFrom(serializedMessage);
       if (LOG.isTraceEnabled()) {
-        LOG.trace("Deserialized response '{}'", TextFormat.shortDebugString(msg));
+        LOG.trace(
+            "Deserialized {} '{}'",
+            msg.getClass().getSimpleName(),
+            TextFormat.shortDebugString(msg)
+        );
       }
       return impl.deserialize(msg);
     }
@@ -348,7 +356,11 @@
       Message responseMsg = response.serialize();
       // Serialization of the response may be large
       if (LOG.isTraceEnabled()) {
-        LOG.trace("Serializing response '{}'", TextFormat.shortDebugString(responseMsg));
+        LOG.trace(
+            "Serializing {} '{}'",
+            responseMsg.getClass().getSimpleName(),
+            TextFormat.shortDebugString(responseMsg)
+        );
       }
       serializeMessage(out, responseMsg);
       return out.toArray();
@@ -364,7 +376,11 @@
       Message requestMsg = request.serialize();
       // Serialization of the request may be large
       if (LOG.isTraceEnabled()) {
-        LOG.trace("Serializing request '{}'", TextFormat.shortDebugString(requestMsg));
+        LOG.trace(
+            "Serializing {} '{}'",
+            requestMsg.getClass().getSimpleName(),
+            TextFormat.shortDebugString(requestMsg)
+        );
       }
       serializeMessage(out, requestMsg);
       return out.toArray();