code: private static Opt<String> newHeader(final Opt<Integer> data,
          final ByteArrayOutputStream baos) {
          Opt<String> header = new Opt.Empty<>();
          if (data.get() != ' ' && data.get() != '\t') {
              header = new Opt.Single<>(
                  new Utf8String(baos.toByteArray()).asString()
              );
              baos.reset();
          }
          return header;
      }
docs: Builds current read header.
  @param data Current read character
  @param baos Current read header
  @return Read header