use ;
use ;
use TryInto;
/// Message used by upstream to control the downstream submission rate by adjusting the difficulty
/// target on a specified channel.
///
/// All submits leading to hashes higher than the specified target are expected to be rejected by
/// the upstream.
///
/// [`SetTarget::maximum_target`] is valid until the next [`SetTarget`] message is sent and is
/// applicable for all jobs received on the channel in the future or already received with flag
/// `future_job=true`.
///
/// When this message is sent to a group channel, the maximum target is applicable to all channels
/// in the group.