Summary:
So, all initial operations can now be done synchronously (and on the main thread).
To do so, instancitate `RCTSurface` object and call `synchronouslyWaitForStage:timeout:` method like that:
RCTSurface *surface = [[RCTSurface alloc] initWithBridge:... moduleName:... initialProperties:...];
BOOL success = [surface synchronouslyWaitForStage:RCTSurfaceStageSurfaceDidInitialMounting timeout:timeout];
or
RCTSurfaceHostingView *surfaceHostingView = [[RCTSurfaceHostingView alloc] initWithBridge:... moduleName:... initialProperties:...];
BOOL success = [surfaceHostingView.surface synchronouslyWaitForStage:RCTSurfaceStageSurfaceDidInitialMounting timeout:timeout];
Reviewed By: fkgozali
Differential Revision: D7014178
fbshipit-source-id: c3c13904a3587ff2a222fa71623c40c8f30bc8af
b7fbeb253a