The current user, when the host supplied one. Providers should fail closed (return []) if they require a user and none is present.
Maximum number of suggestions the editor will display; providers should honor it.
The metadata provider scoping this editor instance, when the host supplied one (multi-provider support).
The text typed after the trigger character (may be empty — show the full list).
Request passed to ComposerTriggerProvider.GetSuggestions each time the user types after an active trigger character.