Sets the priority of the request.
Allowed values: ISDMRequest.PRIORITY_HIGH and ISDMRequest.PRIORITY_NORMAL. In case of a different value, the default ISDMRequest.PRIORITY_NORMAL will be used by the network. If the network layer finds an ISDMRequest with ISDMRequest.PRIORITY_HIGH priority in the queue, that request will be executed first. If there are more than one IRequests with ISDMRequest.PRIORITY_HIGH priority, the network layer will choose an execution order. If the priority is not one of the predefined values, the priority will be set by default to ISDMRequest.PRIORITY_NORMAL