apollo-core/src/main/java/com/ctrip/framework/foundation/internals/io/ByteOrderMark.java/ByteOrderMark/toString
class ByteOrderMark:  @Override
  public String toString() {
    final StringBuilder builder = new StringBuilder();
    builder.append(getClass().getSimpleName());
    builder.append('[');
    builder.append(charsetName);
    builder.append(": ");
    for (int i = 0; i < bytes.length; i++) {
      if (i > 0) {
        builder.append(",");
      }
      builder.append("0x");
      builder.append(Integer.toHexString(0xFF & bytes[i]).toUpperCase());
    }
    builder.append(']');
    return builder.toString();
  }