Macro declare_client_streaming

macro_rules! declare_client_streaming {
    ($service:ident, $m_input:ident, $m_update:ident, $m_output:ident) => { ... };
}

Declare a message to be a server streaming message for a service.

Example:

declare_client_streaming!(TestService, TestRequest, TestUpdate, TestResponse);

This is equivalent to:

impl Msg<TestService> for TestRequest {
    type Pattern = ClientStreamingPattern;
}

impl ClientStreamingMsg<TestService> for TestRequest {
    type Update = TestUpdate;
    type Response = TestResponse;
}