toString method
A string representation of this object.
Some classes have a default textual representation,
often paired with a static parse function (like int.parse).
These classes will provide the textual representation as
their string representation.
Other classes have no meaningful textual representation
that a program will care about.
Such classes will typically override toString to provide
useful information when inspecting the object,
mainly for debugging or logging.
Implementation
@override
String toString() {
  var anyFormatStr = _anyFormat ? "fl_any_format$paramSeparator" : "";
  var quantizationStr = (_quantization != null)
      ? "${defaultValuesSeparator}qmax_$_quantization"
      : "";
  var chromaSubSamplingStr = (_chromaSubSampling != null)
      ? "$defaultValuesSeparator${_chromaSubSampling.toString()}"
      : "";
  return "${anyFormatStr}q_$level$chromaSubSamplingStr$quantizationStr";
}