||(optional) Choice of host for the virtual machine, in case this
operation causes the virtual machine to power on.
If a snapshot was taken while a virtual machine was powered on, and this operation
is invoked after the virtual machine was powered off, the operation causes the
virtual machine to power on to reach the snapshot state. This parameter can be
used to specify a choice of host where the virtual machine should power on.
If this parameter is not set and the vBalance feature is configured for automatic
load balancing, a host is automatically selected. Otherwise, the virtual machine
keeps its existing host affiliation.