open fun startObject(): O?
Indicates the beginning of an object in the JSON input. This method will be called when reading
the opening curly bracket character ('{').
This method may return an object to handle subsequent parser events for this object. This object handler will be provided in all calls to startObjectName(), endObjectName(), startObjectValue(), endObjectValue(), and endObject() for this object.
Return
a handler for this object, or null if not needed