Resolves the promise when the observable's state matches the predicate.
OptionalisError: (state: T) => unknownOptionalcancellationToken: CancellationTokenResolves the promise when the observable's state matches the predicate.
OptionalisError: (state: T) => unknownOptionalcancellationToken: CancellationToken
Resolves the promise when the observable's state matches the predicate.