addAnnotationJson abstract method
Adds an annotation from an Instant JSON string (low-level transport).
Prefer the typed addAnnotation for most use cases.
jsonAnnotation is a JSON-encoded annotation object.
attachment is an optional base64-encoded image attachment for stamp/image
annotations.
Returns the Instant JSON string of the created annotation.
Implementation
Future<String> addAnnotationJson(String jsonAnnotation, {String? attachment});