Confusing API for parsing and serializing

[renyuneyun]

The library doesn't have a consistent API for use in parsing and serializing RDF files (currently only Turtle, if I understand correctly), also without clear/correct documents.

For example:

• parseTurtle() and parse() both exist
  • parse() is marked deprecated, which makes sense
  • However, their internals are different, leading to different parsed results, and how the Graph object should be used subsequently
  • A cleaner way is to provide a NewGraph class for the new parsing method, if it's not stable enough, and then fully replace the old one after mature; or use a different branch, etc
• graph.serialize() and graph.serializedString both exist, without clear documentation
• graph.serialize() has an optional parameter that is confusing, and also leading to inconsistent behaviours

[gjwgit]

Yes, a WIP. There is more recent and active work on https://pub.dev/packages/rdf_core.