restart method
Builds a restart entry re-issuing the original tool request.
The optional resumed payload is stored under the resumed metadata key
(mirroring the JS restart(interrupt, resumedMetadata) convention). The
tool reads it back via ToolFnArgs.resumed.
Implementation
ToolRequestPart restart([Map<String, dynamic>? resumed]) => ToolRequestPart(
toolRequest: ToolRequest(name: name, ref: ref, input: input),
metadata: resumed != null ? {'resumed': resumed} : null,
);