macro_rules! stream {
($k:ty => $v:ty; $r:ty) => {
stream![($k, $v); $r]
};
($d:ty; $r:ty) => {
differential_dataflow::collection::Collection<
timely::dataflow::scopes::Child<
'a,
timely::worker::Worker<timely::communication::allocator::Process>,
crate::timestamp::DateTime,
>,
$d,
$r,
>
};
}