Roadmap

Foundation

• Candidate, status, weight, selection, and policy contracts.
• Round robin, random, weighted random, least loaded, P2C, and rendezvous.
• Deterministic tests, generated policy invariants, and rustdoc examples.
• Criterion benchmarks and recorded baselines for poise-core selection and membership-change cost. Dispatch, health, and discovery remain unmeasured.
• Naming, licensing, security policy, MSRV policy, and governance before publication.

Dynamic systems

• Immutable versioned snapshots with keyed backend identity.
• Atomic snapshot publication and graceful draining.
• Smooth weighted round robin with identity-keyed state migration.
• Load trackers for in-flight requests and peak-EWMA latency.
• Rolling success-rate and overload penalties.
• Passive health and circuit breaking with bounded recovery probes.
• Executor-neutral active probe scheduling with threshold transitions.
• Group-relative success-rate outlier detection with safety caps.

Ecosystem integration

• Tower adapter with retained readiness, load tracking, and cancellation.
• Transactional static snapshot-to-Tower reconciliation.
• Runtime-neutral coalescing snapshot streams and Tower reconciliation.
• Optional Tokio active-health and discovery conveniences without making Tokio a core dependency.
• tracing spans and metrics with bounded-cardinality defaults.

Advanced policies

• Weighted rendezvous with proportional capacity and minimal reweight churn.
• Bounded weighted virtual-node ring hash with transactional rebuilds.
• Prime-sized, transactionally rebuilt Maglev lookup tables.
• Weighted rendezvous affinity with prospective concurrent-load bounds.
• Weighted priority tiers, overprovisioned failover, and panic thresholds.
• Health-adjusted locality weighting and cross-locality spillover.
• Retry and hedge selection that excludes already-attempted backends.
• Adaptive concurrency and capacity-aware routing.

Verification bar

Every stable policy should have:

• unit, property, and deterministic replay tests;
• distribution and disruption tests where applicable;
• criterion benchmarks across small and large backend sets;
• documented time, memory, and allocation complexity;
• behavior documented for empty sets, ineligible sets, ties, overflow, membership churn, and seeded randomness;
• comparison against a reference implementation, where the shipped code is optimised away from its specification. Cached and scratch-retaining policies are compared against a policy with no history; for a policy whose implementation is its specification, a reference would be a copy and is not required.