Constructs a model and records it with its metadata in a weakset. Allows for
the separate storage of core model fields and Amplify/DataStore metadata
fields that the customer app does not want exposed.
Param: modelConstructor
The model constructor.
Param: init
Init data that would normally be passed to the constructor.
Constructs a model and records it with its metadata in a weakset. Allows for the separate storage of core model fields and Amplify/DataStore metadata fields that the customer app does not want exposed.