Function enqueue 

pub async fn enqueue(
    conn: &mut PgConnection,
    webhooks: &Webhooks,
    event: &Event,
) -> Result<u64, ApiError>

Queues an event for every destination that hears it and may hear about this person. Returns how many rows were written.

Takes the caller’s connection so it runs inside the caller’s transaction: the fact and its announcement commit together or not at all.