Type Alias SecurityKey 

pub type SecurityKey = String;

股票行情缓存 key: “market_code” (如 “1_00700”) 或 broker-aware “market_code@b1007”.

v1.4.110 Phase 2 Slice 5: cache key encoding 仍是 String (Phase 5 不 引入新 hash domain), broker-aware 后缀由 QotSecurityKey::cache_key() 编码:

• no_broker: "91_BTCUSDT" (与升级前等价)
• broker-aware: "91_BTCUSDT@b1007" (Phase 3 之后启用)

Aliased Type

pub struct SecurityKey { /* private fields */ }