perf[bytebuf]: adjust Padding

protocol/src/main/java/com/zfoo/protocol/buffer/ByteBufUtils.java

@@ -371,9 +371,25 @@ public abstract class ByteBufUtils {
         // 预估需要写入的字节数，并预留位置
         var beforeWriteIndex = byteBuf.writerIndex();
         var maxLength = ByteBufUtil.utf8MaxBytes(value);
-        writeInt(byteBuf, maxLength);
-        byteBuf.writeCharSequence(value, StringUtils.DEFAULT_CHARSET);
-        adjustPadding(byteBuf, maxLength, beforeWriteIndex);
+        var writeIntCountByte = writeInt(byteBuf, maxLength);
+
+        var length = byteBuf.writeCharSequence(value, StringUtils.DEFAULT_CHARSET);
+
+        var currentWriteIndex = byteBuf.writerIndex();
+
+        // 因为写入的是可变长的int，如果预留的位置过多，则清除多余的位置
+        var padding = writeIntCountByte - writeIntCount(length);
+        if (padding == 0) {
+            byteBuf.writerIndex(beforeWriteIndex);
+            writeInt(byteBuf, length);
+            byteBuf.writerIndex(currentWriteIndex);
+        } else {
+            var retainedByteBuf = byteBuf.retainedSlice(currentWriteIndex - length, length);
+            byteBuf.writerIndex(beforeWriteIndex);
+            writeInt(byteBuf, length);
+            byteBuf.writeBytes(retainedByteBuf);
+            ReferenceCountUtil.release(retainedByteBuf);
+        }
     }
 
     public static String readString(ByteBuf byteBuf) {