public long Copy(Stream inputStream, Stream outputStream)
{
if (buffer == null)
{
buffer = new byte[bufferSize];
}
long copied = 0;
while (true)
{
int count = inputStream.Read(buffer, 0, buffer.Length);
if (count <= 0)
{
break;
}
outputStream.Write(buffer, 0, count);
copied += count;
}
return copied;
}