Function buffer_hash_to_tx_fetcher 

pub fn buffer_hash_to_tx_fetcher(
    tx_fetcher: &mut TransactionFetcher,
    hash: FixedBytes<32>,
    peer_id: FixedBytes<64>,
    tx_encoded_length: Option<usize>,
)

Available on crate features test-utils only.

Announces a hash to the tx fetcher on behalf of the given peer, without sending a request.