to Map
If the type of a MPIActionis MPIActionType.TAKEVORTEX or MPIActionType.EXITVORTEX, toMap represents the MPIMap of destination; otherwise, toMap is null.
If the type of a MPIActionis MPIActionType.TAKEVORTEX or MPIActionType.EXITVORTEX, toMap represents the MPIMap of destination; otherwise, toMap is null.