object to a JSON String.
Directly serializable values are num, String, bool, and Null, as well as some List and Map values. For List, the elements must all be serializable. For Map, the keys must be String and the values must be serializable.
If a value of any other type is attempted to be serialized, the
toEncodable function provided in the constructor is called with the value
as argument. The result, which must be a directly serializable value, is
serialized instead of the original value.
If the conversion throws, or returns a value that is not directly
serializable, a JsonUnsupportedObjectError exception is thrown.
If the call throws, the error is caught and stored in the
object should not change during serialization.
If an object is serialized more than once, convert may cache the text for it. In other words, if the content of an object changes after it is first serialized, the new values may not be reflected in the result.
String convert(Object object) => _JsonStringStringifier.stringify(object, _toEncodable, indent);