private void GetBlockHeaderByHashTxSizes(byte[] blockHash, GetBlockHeaderByHashTxsSizeHandler handler) { var managedHash = new hash_t { hash = blockHash }; IntPtr contextPtr = CreateContext(handler, managedHash); ChainNative.kth_chain_async_block_header_by_hash_txs_size(nativeInstance_, contextPtr, managedHash, internalGetBlockHeaderByHashTxsSizeHandler_); }