pub(super) const ERR_NOT_INIT: &str = "Not initialized yet";
pub(super) const ERR_INIT: &str = "Already initialized";
pub(super) const ERR_STARTED: &str = "Already running";
pub(super) const ERR_NOT_STARTED: &str = "Not running yet";
pub(super) const ERR_STOPPED: &str = "Already stopped";