Constructs an asynchronous function that discards its input and uses the closure f
to produce its output.
Constructs an asynchronous function from an ordinary Scala function.
Constructs an asynchronous function from an ordinary Scala function.
WARNING: this overload requires the function to come with its own ExecutionContext and ignore the one passed to AsyncFunc.apply, which is usually not what you want.
Constructs an asynchronous function from an ordinary Scala function which takes a separate ExecutionContext.