DerivableClient

A factory is a Client that carries no request options, so it can be passed to an operation directly. Calling it with RequestOptions returns a plain, non-callable Client value for one call and performs no I/O. That value cannot be called again: client()() fails to compile and throws a TypeError at runtime. The seven known fields are copied from the argument into a fresh options object, unknown fields are ignored, and fields whose value is undefined are omitted. Nested heartbeat, protocols, and reconnect values are kept by reference. There is no parent overlay: client(), client(undefined), and client({}) all return a client with no request options. A getter that throws escapes the call and is not converted into a fault; the factory stays usable.