participantId property
The identifier of the participant, for example 'test-user' or 'gemini'.
The participant ID can contain lowercase letters, numbers, and hyphens;
that is, it must match the regular expression:
^[a-z]([a-z0-9-]{0,61}[a-z0-9])?$. The maximum length is 63 characters.
Optional.
Implementation
core.String? participantId;