Function store_match 

pub fn store_match(
    dimension_key: Vec<u8>,
    tx_seq: u64,
    event_idx: u32,
) -> (Key, Value)

Build a (Key, Value) pair that adds the event identified by (tx_seq, event_idx) to the bitmap for its dimension and bucket. The merge operator unions this single-bit operand with whatever’s already on disk.