private void FetchConfirmedTransactions(PaymentAddress address, UInt64 limit, UInt64 fromHeight, Action <ErrorCode, HashList> handler)
{
GCHandle handlerHandle = GCHandle.Alloc(handler);
IntPtr handlerPtr = (IntPtr)handlerHandle;
ChainNative.chain_fetch_confirmed_transactions(nativeInstance_, handlerPtr, address.NativeInstance, limit, fromHeight, internalFetchTxnsHandler_);
}