Function IOPMSleepSystem 

pub extern "C-unwind" fn IOPMSleepSystem(fb: io_connect_t) -> IOReturn

Available on crate features libc and pwr_mgt only.

Request that the system initiate sleep.

For security purposes, caller must be root or the console user.

Parameter fb: Port used to communicate to the kernel, from IOPMFindPowerManagement.

Returns: Returns kIOReturnSuccess or an error condition if request failed.