mapFuture with ec.prepare()

[WayneWang12]

In module lagom-server, there is one line of mapFuture like:

    inMemoryBodyParser(playRequestHeader).mapFuture {
      ... // code is omitted
    }

The same operation in play, mapFuture is with ec.prepare() which like:

    parser(rh).mapFuture {
        ... // code is omitted
    }(ExecCtxUtils.prepare(executionContext))

Can lagom obey the same behavior with play? Context is that I'm doing a ContextPropagating which like a RequestContext in asynchronous environment. And mapFuture without ec.preprare() makes it impossible.