apollo-core/src/main/java/com/ctrip/framework/foundation/internals/io/BOMInputStream.java/BOMInputStream/find
class BOMInputStream:  private ByteOrderMark find() {
    for (final ByteOrderMark bom : boms) {
      if (matches(bom)) {
        return bom;
      }
    }
    return null;
  }