(Optional) A Map of parameters to set in the VM's "extra config" object. This data can then be read back at a later stage. In the case of parameters whose name starts "guestinfo.", the parameter can be read by the VMware Tools on the client OS. e.g. a variable named "guestinfo.Foo" with value "Bar" could be read on the guest using the command-line vmtoolsd --cmd "info-get guestinfo.Foo".