import Foundation struct RequestRegistry: ~Copyable, Sendable { private let requests = Mutex<[Int64: T]>([:]) func add(requestId: Int64, request: T) { requests.withLock { $0[requestId] = request } } @discardableResult func remove(requestId: Int64) -> T? { requests.withLock { $0.removeValue(forKey: requestId) } } }