Struct StrandRegistry 

pub struct StrandRegistry {
    pub overflow_count: AtomicU64,
    /* private fields */
}

Lock-free strand registry

Provides O(n) registration (scan for free slot) and O(n) unregistration. This is acceptable because:

1. N is bounded (default 1024)
2. Registration/unregistration are infrequent compared to strand work
3. No locks means no contention, just atomic ops

Fields

overflow_count: AtomicU64

Number of slots that couldn’t be registered (registry full)

Implementations

impl StrandRegistry

pub fn register(&self, strand_id: u64) -> Option<usize>

Register a strand, returning the slot index if successful

Uses CAS to atomically claim a free slot. Returns None if the registry is full (strand still runs, just not tracked).

pub fn unregister(&self, strand_id: u64) -> bool

Unregister a strand by ID

Scans for the slot containing this strand ID and clears it. Returns true if found and cleared, false if not found.

Note: ABA problem is not a concern here because strand IDs are monotonically increasing u64 values. ID reuse would require 2^64 spawns, which is practically impossible (at 1 billion spawns/sec, it would take ~584 years).

pub fn active_strands(&self) -> impl Iterator<Item = (u64, u64)> + '_

Iterate over active strands (for diagnostics)

Returns an iterator of (strand_id, spawn_time) for non-empty slots. Note: This is a snapshot and may be slightly inconsistent due to concurrent updates.

pub fn capacity(&self) -> usize

Get the registry capacity