/// <summary>
/// Gets a value by its key.
/// </summary>
/// <typeparam name="TKey">Key type.</typeparam>
/// <param name="txn">Transaction.</param>
/// <param name="key">Key.</param>
/// <returns>Value converter or null if not exists.</returns>
public static GetByOperation GetBy <TKey>(this LightningTransaction txn, TKey key)
{
return(txn.GetBy(txn.OpenDatabase(), key));
}
