func (ua *UIAutomator) Sleep() error {
	return ua.post(
		&RPCOptions{
			Method: "sleep",
			Params: []interface{}{},
		},
		nil,
		nil,
	)
}
/*
Trun off the screen
package uiautomator
import (
	"reflect"
	"time"
)
func (ua *UIAutomator) WakeUp() error {
	return ua.post(
		&RPCOptions{
			Method: "wakeUp",
			Params: []interface{}{},
		},
		nil,
		nil,
	)
}