Struct SharedDriverRegistration 

pub struct SharedDriverRegistration {
    pub adapter: &'static str,
    pub driver: &'static str,
    pub share_capability: ShareCapability,
    pub resource_key: fn(&HashMap<String, String>) -> Result<ResourceKey, String>,
}

SRD-35 Push B: declares that a (adapter, driver) pair supports pool-shared instances. Drivers that submit one of these opt into the resource pool’s Shared policy path: instead of a fresh Arc<dyn DriverAdapter> per phase, the pool caches the adapter under Self::resource_key and reuses it across every phase whose params produce the same key.

Drivers without a SharedDriverRegistration continue to use Push A’s LegacyAdapterResource shim, which is PerPhase-isolated. Migration is opt-in per driver.

Fields

adapter: &'static str

Adapter name this registration applies to (e.g. "cql"). Pairs with Self::driver for lookup.

driver: &'static str

Driver identifier (e.g. "cassandra-cpp", "scylla"). Distinguishes registrations when the same adapter has multiple driver implementations.

share_capability: ShareCapability

Strongest sharing the driver supports. Default Shared for typical pool-friendly drivers; stricter only if the driver type can’t be safely shared.

resource_key: fn(&HashMap<String, String>) -> Result<ResourceKey, String>

Pure function that derives the resource key from the adapter’s params. Two phases with the same key share an instance under Shared policy. SRD-35 §“Instance-shaping vs shell-shaping params” — only instance-shaping params (hosts, keyspace, …) belong here; per-statement and per-phase knobs MUST NOT.

Trait Implementations

impl Collect for SharedDriverRegistration