private void FetchTransaction(byte[] txHash, bool requireConfirmed, Action <ErrorCode, Transaction, UInt64, UInt64> handler)
{
var managedHash = new hash_t
{
hash = txHash
};
IntPtr contextPtr = CreateContext(handler, managedHash);
ChainNative.chain_fetch_transaction(nativeInstance_, contextPtr, managedHash, requireConfirmed ? 1 : 0, internalFetchTransactionHandler_);
}