code: public static Scheme of(SerializationFormat serializationFormat, SessionProtocol sessionProtocol) {
          return SCHEMES.get(requireNonNull(serializationFormat, "serializationFormat").uriText() + '+' +
                             requireNonNull(sessionProtocol, "sessionProtocol").uriText());
      }
docs: Returns the {@link Scheme} of the specified {@link SerializationFormat} and {@link SessionProtocol}.
  This method returns the same {@link Scheme} instance for the same combination of
  {@link SerializationFormat} and {@link SessionProtocol}.