docs: public byte[] getByteBuffer(int expected) {
  		if (this.byteBuffer.length >= expected) {
  			return byteBuffer;
  		} else if (expected < MAX_SIZE) {
  			// ?预先设置多一点
  			byteBuffer = new byte[(int) (expected * 1.2)];
  			return byteBuffer;
  		} else {
  			return EMPTY_BYTE_ARRAY;
  		}
  
  	}