Add JMH benchmarks for Protobuf message converter

This commit re-generates the protobuf Java classes with a recent version
of the protoc binary and adds JMH benchmarks that exercise the message
converter for both the reading and writing cases.

See gh-29496

spring-web/src/jmh/java/org/springframework/http/converter/protobuf/ProtobufHttpMessageConverterBenchmark.java

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2002-2023 the original author or 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.http.converter.protobuf;
+
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Random;
+import java.util.stream.Stream;
+
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.Param;
+import org.openjdk.jmh.annotations.Scope;
+import org.openjdk.jmh.annotations.Setup;
+import org.openjdk.jmh.annotations.State;
+import org.openjdk.jmh.infra.Blackhole;
+
+import org.springframework.protobuf.Msg;
+import org.springframework.protobuf.SecondMsg;
+import org.springframework.web.testfixture.http.MockHttpInputMessage;
+import org.springframework.web.testfixture.http.MockHttpOutputMessage;
+
+/**
+ * Benchmarks for the {@link ProtobufHttpMessageConverter}.
+ *
+ * @author Brian Clozel
+ */
+@BenchmarkMode(Mode.Throughput)
+public class ProtobufHttpMessageConverterBenchmark {
+
+	@Benchmark
+	public void writeMessages(BenchmarkWriteData data, Blackhole bh) throws IOException {
+		for (Msg message : data.messages) {
+			MockHttpOutputMessage outputMessage = new MockHttpOutputMessage();
+			data.converter.write(message, ProtobufHttpMessageConverter.PROTOBUF, outputMessage);
+			bh.consume(outputMessage);
+		}
+	}
+
+	/**
+	 * Benchmark data holding typical Protobuf messages to be converted to bytes.
+	 */
+	@State(Scope.Benchmark)
+	public static class BenchmarkWriteData {
+
+		@Param({"40"})
+		public int messageCount;
+
+		public List<Msg> messages;
+
+		public ProtobufHttpMessageConverter converter = new ProtobufHttpMessageConverter();
+
+
+		@Setup(Level.Trial)
+		public void createMessages() {
+			Random random = new Random();
+			this.messages = Stream.generate(() -> createMessage(random.nextInt())).limit(this.messageCount).toList();
+		}
+
+		private Msg createMessage(int randomValue) {
+			return Msg.newBuilder().setFoo(String.valueOf(randomValue)).setBlah(SecondMsg.newBuilder().setBlah(randomValue).build()).build();
+		}
+
+	}
+
+
+	@Benchmark
+	public void readMessages(BenchmarkReadData data, Blackhole bh) throws IOException {
+		for (byte[] message : data.messages) {
+			MockHttpInputMessage inputMessage = new MockHttpInputMessage(message);
+			bh.consume(data.converter.read(Msg.class, inputMessage));
+		}
+	}
+
+	/**
+	 * Benchmark data holding typical Protobuf messages to be converted to bytes.
+	 */
+	@State(Scope.Benchmark)
+	public static class BenchmarkReadData {
+
+		@Param({"40"})
+		public int messageCount;
+
+		public List<byte[]> messages;
+
+		public ProtobufHttpMessageConverter converter = new ProtobufHttpMessageConverter();
+
+		@Setup(Level.Trial)
+		public void createMessages() {
+			Random random = new Random();
+			this.messages = Stream.generate(() -> createMessage(random.nextInt())).limit(this.messageCount).toList();
+		}
+
+		private byte[] createMessage(int randomValue) {
+			return Msg.newBuilder().setFoo(String.valueOf(randomValue)).setBlah(SecondMsg.newBuilder().setBlah(randomValue).build()).build().toByteArray();
+		}
+
+	}
+}