Function IOPMFindPowerManagement 

pub extern "C-unwind" fn IOPMFindPowerManagement(
    master_device_port: mach_port_t,
) -> io_connect_t

Available on crate features libc and pwr_mgt only.

Finds the Root Power Domain IOService.

Parameter master_device_port: Just pass in MACH_PORT_NULL for master device port.

Returns: Returns a io_connect_t handle on the root domain. Must be released with IOServiceClose() when done.