Macro erdos::connect_3_write

macro_rules! connect_3_write {
    ($t:ty, $config:expr) => { ... };
    ($t:ty, $config:expr, $($s:ident),*) => { ... };
}

Connects read streams to an operator that writes on 3 streams.

Use: let (read_stream_3, read_stream_4, read_stream_5) = connect_3_write!(MyOp, arg, read_stream_1, read_stream_2, ...);