code: private static String readToken(Buffer buffer) {
      try {
        long tokenSize = buffer.indexOfElement(TOKEN_DELIMITERS);
        if (tokenSize == -1L) tokenSize = buffer.size();
  
        return tokenSize != 0L
            ? buffer.readUtf8(tokenSize)
            : null;
      } catch (EOFException e) {
        throw new AssertionError();
      }
    }
docs: Consumes and returns a non-empty token, terminating at special characters in {@link
  #TOKEN_DELIMITERS}. Returns null if the buffer is empty or prefixed with a delimiter.