function processTagByte(b) {
    if (b & 0x80) {
      parser.error_(inputBytes, pos, 'invalid tag');
    }

    const wireType = b & 0x07;
    if (wireType != 2) {
      parser.error_(inputBytes, pos, 'invalid wire type');
    }

    parser.tag_ = b >>> 3;
    if (parser.tag_ != 1 && parser.tag_ != 2 && parser.tag_ != 15) {
      parser.error_(inputBytes, pos, 'unexpected tag');
    }

    parser.state_ = goog.net.streams.PbStreamParser.State_.LENGTH;
    parser.length_ = 0;
    parser.countLengthBytes_ = 0;
  }
@param {number} b A tag byte to process