webSocket(maxFrameSize:shouldUpgrade:onUpgrade:)

@preconcurrency func webSocket(maxFrameSize: WebSocketMaxFrameSize = .`default`, shouldUpgrade: @escaping (@Sendable (Request) -> EventLoopFuture<HTTPHeaders?>) = {
             $0.eventLoop.makeSucceededFuture([:])
         }, onUpgrade: @Sendable @escaping (Request, WebSocket) -> ()) -> Response