Receive one message of the specified type from the test actor and assert that the given predicate accepts it. Use this variant to implement more complicated or conditional processing. Wait time is bounded by the given duration, if specified; otherwise wait time is bounded by remaining time for execution of the innermost enclosing 'within' block, if inside a 'within' block; otherwise by the config value "akka.test.single-expect-default".

public T ExpectMsg<T>(
	Predicate<T> isMessage,
	Nullable<TimeSpan> timeout = null,
	string hint = null
)

member ExpectMsg : 
        isMessage : Predicate<'T> * 
        ?timeout : Nullable<TimeSpan> * 
        ?hint : string 
(* Defaults:
        let _timeout = defaultArg timeout null
        let _hint = defaultArg hint null
*)
-> 'T