/// <summary>
/// Gets the number of bytes in the packet capture between index1 and index2 in the index file
/// </summary>
/// <param name="index1">the start index (includive)</param>
/// <param name="index2">the end index (exclusive)</param>
/// <returns>the packet count</returns>
public long GetDataSpan(long index1, long index2)
{
long start, end;
IndexFile.GetDataIndices(index1, index2, out start, out end);
return(end - start);
}