Macro connect_stream 

macro_rules! connect_stream {
    (return $stream:expr, $widget:expr, $event:ident($($args:pat),*), $msg:expr) => { ... };
    ($widget:expr, $event:ident($($args:pat),*), $other_stream:expr, $msg:expr) => { ... };
    ($src_stream:ident @ $message:pat, $dst_stream:expr, $msg:expr) => { ... };
}

Connect events to sending a message. Similar to connect! but wants a stream instead of a component.

Rules

1. Send $msg to $other_stream when the GTK+ $event is emitted on $widget.

2. Send $msg to $widget when the $message is received on $stream.