Loads a JSON stream from the content of `filename` and parses it.
If the file is large or shared between processes, [method@Json.Parser.load_from_mapped_file] may be a more efficient way to load it.
See also: [method@Json.Parser.load_from_data]
| this |
a parser |
| filename |
the path for the file to parse |
|
`TRUE` if the file was successfully loaded and parsed. |