Enum WorkerSelection 

pub enum WorkerSelection {
    PreferTiers(Vec<Option<String>>),
    Required(BTreeSet<String>),
}

How an UNPINNED outbox row (row.node == None) must be dispatched given its namespace’s NamespacePlacement — the SINGLE decision consulted by WorkerOutboxDispatch, which since #52 R4 selects for BOTH transports, so Prefer (spill) versus Pinned (require and wait, NEVER spill) is decided once for every row, whatever the chosen worker is delivered over.

This is consulted ONLY for an unpinned row: an authored Some(N) pin is authoritative and never enters this path. The result is a pure worker-SELECTION input; it never mutates the recorded row’s node (the determinism invariant, CP-Phase-2 §2.4).

Variants

PreferTiers(Vec<Option<String>>)

Unplaced/Prefer: try the ordered tiers (each preferred label, then the None spill), stopping at the first tier with a live worker. Unplaced collapses to the single None any-worker tier.

Required(BTreeSet<String>)

Pinned{L}: require a worker whose advertised node ∈ L, and WAIT when none is live — NEVER a None spill to an any-node worker (CP-Phase-2 §2.5, P2-I1). An empty required set can never be satisfied by any labelled worker, so it stalls until the namespace’s placement is relaxed — the correct “isolation > availability” behaviour of a hard pin with no admissible node.

Trait Implementations

impl Clone for WorkerSelection

fn clone(&self) -> WorkerSelection

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for WorkerSelection

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

Formats the value using the given formatter.

impl Eq for WorkerSelection

impl PartialEq for WorkerSelection

fn eq(&self, other: &WorkerSelection) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for WorkerSelection