github.com/golang/protobuf/jsonpb.anyResolver.FindExtensionByNumber (method, view implemented interface methods)

one use

	github.com/golang/protobuf/jsonpb (current package)
		json.go#L47: func (r anyResolver) FindExtensionByNumber(message protoreflect.FullName, field protoreflect.FieldNumber) (protoreflect.ExtensionType, error) {