Function into_consolidatable_updates_startup 

pub(crate) fn into_consolidatable_updates_startup(
    updates: Vec<StateUpdate>,
    ts: Timestamp,
) -> Vec<(StateUpdateKind, Timestamp, Diff)>

Convert updates into a Vec that can be consolidated by doing the following:

• Update the timestamp of each update to the same value.
• Convert the diff of each update to a type that implements differential_dataflow::difference::Semigroup.

WARNING: Do not call outside of startup.