MessagingCenter Exception in Xamarin.Forms 1.4

I am getting the following MessagingCenter exception thrown after upgrading to Xamarin Forms 1.4. Is there an appropriate workaround for the MessagingCenter in the latest Xamarin.Forms versions?

Exception:
"An exception of type 'System.InvalidOperationException' occurred in mscorlib.dll but was not handled in user code

Additional information: Collection was modified; enumeration operation may not execute."

Code:
MessagingCenter.Send(this, "Close");