Function IOGetSystemLoadAdvisory 

pub extern "C-unwind" fn IOGetSystemLoadAdvisory() -> IOSystemLoadAdvisoryLevel

Available on crate feature pwr_mgt only.

Returns a hint about whether now would be a good time to perform time-insensitive work.

Based on user and system load, IOGetSystemLoadAdvisory determines “better” and “worse” times to run optional or time-insensitive CPU or disk work.

Applications may use this result to avoid degrading the user experience. If it is a “Bad” or “OK” time to perform work, applications should slow down and perform work less aggressively.

There is no guarantee that the system will ever be in “Great” condition to perform work - all essential work must still be performed even in “Bad”, or “OK” times. Completely optional work, such as updating caches, may be postponed indefinitely.

Note: You may more efficiently read the SystemLoadAdvisory level using notify_get_state() instead of IOGetSystemLoadAdvisory. The results are identical. notify_get_state() requires that you pass the token argument received by registering for SystemLoadAdvisory notifications.

Returns: IOSystemLoadAdvisoryLevel - one of:

• kIOSystemLoadAdvisoryLevelGreat - A Good time to perform time-insensitive work.
• kIOSystemLoadAdvisoryLevelOK - An OK time to perform time-insensitive work.
• kIOSystemLoadAdvisoryLevelBad - A Bad time to perform time-insensitive work.