The Delphi equivalent is Application.ProcessMessages. There is also an API
function called Yield that seems to do the same thing, but it isn't safe to
use from most Delphi applications.
Steve Teixeira explains:
You should not use Yield() unless your application is *guaranteed* not
to receive any messages (ie, your application contains no windows).
Instead, the way to do this in Delphi is to call
Application.ProcessMessages. ProcessMessage encapsulates a
PeekMessage() loop, which is the correct "API-way" to do this.