Returns the current time of clock type, in seconds.
This function is not idempotent unlike the Now variable, so every call may return a new value.
"boottime"— time since device startup, including device sleep/doze duration, guaranteed monotonic.
"monotonic"— time since device startup, excluding device sleep/doze duration.
"realtime"— current unix timestamp, may jump backwards or forwards unpredictably. See also Now variable.