boolean read(ReadBuffer b) {
      byte bool = b.readByte();
      if (bool < 0 || bool > 1) {
        throw new IllegalArgumentException("Malformed: invalid boolean value at byte " + b.pos());
      }
      return bool == 1;
    }
@param length is greater than zero
zipkin/src/main/java/zipkin2/internal/Proto3Fields.java