Improve new DefaultChannelId (#13960)

Motivation:
The instantiation process of DefaultChannelId presents opportunities for
optimization.

Modifications:
Use the local stack when creating an instance.
Employ `Unsafe`.

Result:
Enhanced Performance.

microbench/src/main/java/io/netty/microbench/channel/DefaultChannelIdBenchmark.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2024 The Netty Project
+ *
+ * The Netty Project licenses this file to you 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 io.netty.microbench.channel;
+
+import io.netty.channel.DefaultChannelId;
+import io.netty.microbench.util.AbstractMicrobenchmark;
+import org.openjdk.jmh.annotations.Benchmark;
+import org.openjdk.jmh.annotations.BenchmarkMode;
+import org.openjdk.jmh.annotations.Fork;
+import org.openjdk.jmh.annotations.Level;
+import org.openjdk.jmh.annotations.Measurement;
+import org.openjdk.jmh.annotations.Mode;
+import org.openjdk.jmh.annotations.OutputTimeUnit;
+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.annotations.Warmup;
+
+import java.util.concurrent.TimeUnit;
+
+@State(Scope.Benchmark)
+@BenchmarkMode(Mode.Throughput)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@Fork(2)
+@Warmup(iterations = 5, time = 1)
+@Measurement(iterations = 8, time = 1)
+public class DefaultChannelIdBenchmark extends AbstractMicrobenchmark {
+
+    @Param({ "false", "true" })
+    private boolean noUnsafe;
+
+    @Setup(Level.Trial)
+    public void setup() {
+        System.setProperty("io.netty.noUnsafe", Boolean.valueOf(noUnsafe).toString());
+    }
+
+    @Benchmark
+    public DefaultChannelId newInstance() {
+        return DefaultChannelId.newInstance();
+    }
+
+}

transport/src/main/java/io/netty/channel/DefaultChannelId.java

@@ -30,6 +30,7 @@
 
 import static io.netty.util.internal.MacAddressUtil.defaultMachineId;
 import static io.netty.util.internal.MacAddressUtil.parseMAC;
+import static io.netty.util.internal.PlatformDependent.BIG_ENDIAN_NATIVE_ORDER;
 
 /**
  * The default {@link ChannelId} implementation.
@@ -189,48 +190,59 @@ static int defaultProcessId() {
     private transient String longValue;
 
     private DefaultChannelId() {
-        data = new byte[MACHINE_ID.length + PROCESS_ID_LEN + SEQUENCE_LEN + TIMESTAMP_LEN + RANDOM_LEN];
+        final byte[] data = new byte[MACHINE_ID.length + PROCESS_ID_LEN + SEQUENCE_LEN + TIMESTAMP_LEN + RANDOM_LEN];
         int i = 0;
 
         // machineId
         System.arraycopy(MACHINE_ID, 0, data, i, MACHINE_ID.length);
         i += MACHINE_ID.length;
 
         // processId
-        i = writeInt(i, PROCESS_ID);
+        writeInt(data, i, PROCESS_ID);
+        i += Integer.BYTES;
 
         // sequence
-        i = writeInt(i, nextSequence.getAndIncrement());
+        writeInt(data, i, nextSequence.getAndIncrement());
+        i += Integer.BYTES;
 
         // timestamp (kind of)
-        i = writeLong(i, Long.reverse(System.nanoTime()) ^ System.currentTimeMillis());
+        writeLong(data, i, Long.reverse(System.nanoTime()) ^ System.currentTimeMillis());
+        i += Long.BYTES;
 
         // random
         int random = PlatformDependent.threadLocalRandom().nextInt();
-        i = writeInt(i, random);
+        writeInt(data, i, random);
+        i += Integer.BYTES;
         assert i == data.length;
 
+        this.data = data;
         hashCode = Arrays.hashCode(data);
     }
 
-    private int writeInt(int i, int value) {
-        data[i ++] = (byte) (value >>> 24);
-        data[i ++] = (byte) (value >>> 16);
-        data[i ++] = (byte) (value >>> 8);
-        data[i ++] = (byte) value;
-        return i;
+    private static void writeInt(byte[] data, int i, int value) {
+        if (PlatformDependent.isUnaligned()) {
+            PlatformDependent.putInt(data, i, BIG_ENDIAN_NATIVE_ORDER ? value : Integer.reverseBytes(value));
+            return;
+        }
+        data[i] = (byte) (value >>> 24);
+        data[i + 1] = (byte) (value >>> 16);
+        data[i + 2] = (byte) (value >>> 8);
+        data[i + 3] = (byte) value;
     }
 
-    private int writeLong(int i, long value) {
-        data[i ++] = (byte) (value >>> 56);
-        data[i ++] = (byte) (value >>> 48);
-        data[i ++] = (byte) (value >>> 40);
-        data[i ++] = (byte) (value >>> 32);
-        data[i ++] = (byte) (value >>> 24);
-        data[i ++] = (byte) (value >>> 16);
-        data[i ++] = (byte) (value >>> 8);
-        data[i ++] = (byte) value;
-        return i;
+    private static void writeLong(byte[] data, int i, long value) {
+        if (PlatformDependent.isUnaligned()) {
+            PlatformDependent.putLong(data, i, BIG_ENDIAN_NATIVE_ORDER ? value : Long.reverseBytes(value));
+            return;
+        }
+        data[i] = (byte) (value >>> 56);
+        data[i + 1] = (byte) (value >>> 48);
+        data[i + 2] = (byte) (value >>> 40);
+        data[i + 3] = (byte) (value >>> 32);
+        data[i + 4] = (byte) (value >>> 24);
+        data[i + 5] = (byte) (value >>> 16);
+        data[i + 6] = (byte) (value >>> 8);
+        data[i + 7] = (byte) value;
     }
 
     @Override