constructor(method, requestHeaders, request, headers, response, status, trailers) {
        this.method = method;
        this.requestHeaders = requestHeaders;
        this.requests = request;
        this.headers = headers;
        this.responses = response;
        this.status = status;
        this.trailers = trailers;
    }
A duplex streaming RPC call. This means that the clients sends an
arbitrary amount of messages to the server, while at the same time,
the server sends an arbitrary amount of messages to the client.