/// <summary>
/// Serializes this graph router data source to the given stream.
/// </summary>
/// <param name="stream"></param>
/// <param name="edgeDataSize"></param>
/// <param name="mapFrom"></param>
/// <param name="mapTo"></param>
/// <returns></returns>
public override long Serialize(System.IO.Stream stream, int edgeDataSize,
MappedHugeArray <TEdgeData, uint> .MapFrom mapFrom, MappedHugeArray <TEdgeData, uint> .MapTo mapTo)
{
// make room for size of graph.
long position = 0;
stream.Seek(8, System.IO.SeekOrigin.Begin);
position = position + 8;
// first serialize all graph-data.
position = position +
_graph.Serialize(new LimitedStream(stream), edgeDataSize, mapFrom, mapTo);
// write size of graph.
stream.Seek(0, System.IO.SeekOrigin.Begin);
stream.Write(BitConverter.GetBytes(position), 0, 8);
stream.Seek(position, System.IO.SeekOrigin.Begin);
// serialize tags.
var tagsSize = _tagsIndex.Serialize(new LimitedStream(stream));
position = position + tagsSize;
return(position);
}