Called for all existing event sources when the event listener is created and when a new event source is attached to the listener.
Assembly: mscorlib (in mscorlib.dll)
Event source implementations should be aware that these callbacks are issued for existing event sources when the event listener is instantiated.
In a multithreaded environment, it is possible for OnEventWritten callbacks to occur before the callback.
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)