fn tombstone() -> Self {
        Self {
            block: AIR,
            count: 0,
            evaluated: AIR_EVALUATED,
            block_listen_gate: None,
        }
    }
/// Value used to fill empty entries in the block data vector.
/// This is the same value as [`SpaceBlockData::NOTHING`] but is not merely done
/// by `.clone()` because I haven't decided whether providing [`Clone`] for
/// `SpaceBlockData` is a good long-term API design decision.
Value used to fill empty entries in the block data vector.
Value used to fill empty entries in the block data vector .
fn tombstone() -> Self {
        Self {
            block: AIR,
            count: 0,
            evaluated: AIR_EVALUATED,
            block_listen_gate: None,
        }
    }
fn tombstone ( ) -> Self { Self { block : AIR , count : 0 , evaluated : AIR_EVALUATED , block_listen_gate : None , } }
Value used to fill empty entries in the block data vector.
Value used to fill empty entries in the block data vector .