Struct ShutdownStats 

pub struct ShutdownStats {
    pub aborted_unwinds: u64,
    pub leaked_box_tasks: u64,
    pub unbalanced_normal_shutdowns: u64,
    pub cross_queue_undrained: u64,
}

Counters for abnormal-shutdown paths. Snapshot returned by Runtime::shutdown_stats.

All counters are 0 for a clean shutdown. Any non-zero counter is a signal to investigate — the runtime hit a defensive code path that should be unreachable in normal operation. Users own their observability stack; the runtime emits no logs of its own (per PR 2’s design — see ShutdownStats doc-comment for the user pattern).

Example

let handle = runtime.shutdown_stats();   // Arc<ShutdownStatsAtomics>
drop(runtime);                            // counters fire during drop
let stats = handle.snapshot();            // plain ShutdownStats for matching
if stats.aborted_unwinds != 0
    || stats.leaked_box_tasks != 0
    || stats.unbalanced_normal_shutdowns != 0
    || stats.cross_queue_undrained != 0
{
    // user's own observability — log to wherever they want
    my_logger::warn!("nexus runtime shutdown: {stats:?}");
}

Fields

aborted_unwinds: u64

Executor::drop hit the slab-unwinding 100ms-wait-then-abort path. Indicates a producer thread held a slab task ref past Runtime drop during a panic. The process aborted before this counter could be read — non-zero means a previous run aborted (the counter is preserved across the abort by being stored in the executor’s state, but reading it requires the runtime to have survived; in practice this counter is set just before abort and serves as a guarantee the abort path was hit if the runtime somehow survived).

leaked_box_tasks: u64

Box-allocated tasks the executor couldn’t free during shutdown unwinding (outstanding cross-thread refs, leaked to avoid double-panic). Memory leak, not UAF. Box memory is reclaimed at process exit.

unbalanced_normal_shutdowns: u64

Normal shutdown (no panic in flight) found an all_tasks entry with rc > 0. Debug builds panic. Release builds eprintln + leak. Indicates a producer didn’t release refs before Runtime drop — call Runtime::shutdown_quiesce before drop to surface this as an Err instead.

cross_queue_undrained: u64

Cross-thread queue entries that landed after Runtime drop and were never drained (the leak path inherited from PR 1a’s dispose_terminal off-thread branch). Pure memory leak.

Trait Implementations

impl Clone for ShutdownStats

fn clone(&self) -> ShutdownStats

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ShutdownStats

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ShutdownStats

fn default() -> ShutdownStats

Returns the “default value” for a type.

impl Copy for ShutdownStats