/// <summary>
/// Gets the transactions that are unconfirmed using getrawmempool.
/// This is efficient when many transaction ids are provided.
/// </summary>
public static async Task <IEnumerable <uint256> > GetUnconfirmedAsync(this IRPCClient rpc, IEnumerable <uint256> transactionHashes)
{
uint256[] unconfirmedTransactionHashes = await rpc.GetRawMempoolAsync();
// If there are common elements, then there's unconfirmed.
return(transactionHashes.Intersect(unconfirmedTransactionHashes));
}