static Stream<Arguments> sessionAndEndpointProvider() {
        return Stream.of(
                Arguments.arguments(SessionProtocol.HTTP, backendServer.httpEndpoint()),
                Arguments.arguments(SessionProtocol.H1C, backendServer.httpEndpoint()),
                Arguments.arguments(SessionProtocol.H2C, backendServer.httpEndpoint()),
                Arguments.arguments(SessionProtocol.H1, backendServer.httpsEndpoint()),
                Arguments.arguments(SessionProtocol.H2, backendServer.httpsEndpoint()),
                Arguments.arguments(SessionProtocol.HTTPS, backendServer.httpsEndpoint())
        );
    }
Tests if a request is failed with {@link SessionProtocolNegotiationException} if a session negotiation
with the backend server takes longer than a connection timeout.

<p>Cleartext protocol are not used because the session could immediately complete when a connection is
established with the proxy server.
core/src/test/java/com/linecorp/armeria/client/proxy/ProxyClientIntegrationTest.java