Loads a schema file describing a Transaction Set.
The 'callback' parameter specifies a function which will be called when the operation completes (or an error is encountered). If the 'callback' parameter is not specified, then the method will block and will not return until the operation completes (or an error is encountered).
The callback for this method is defined as:
'err' is the error that occurred. If there was no error, then 'err' is 'null'.
'err' has 2 properties which hold detailed information:
This method parses the File and loads it into an internal schema list. The class will attempt to automatically detect the SchemaFormat.
If the schema file does not exist or cannot be parsed as an EDI schema, the class fails with an error.