Optional_The _meta property is reserved by ACP to allow clients and agents to attach additional metadata to their interactions. Implementations MUST NOT make assumptions about values at these keys.
See protocol docs: Extensibility
A single item of content
Optional ExperimentalmessageUNSTABLE
This capability is not part of the spec yet, and may be removed or changed at any point.
A unique identifier for the message this chunk belongs to.
All chunks belonging to the same message share the same messageId.
A change in messageId indicates a new message has started.
Both clients and agents MUST use UUID format for message IDs.
A streamed item of content