private async Task <TimeSpan> PingAsync(INetworkStream stream, CancellationToken cancellationToken)
{
var buffer = new byte[PingSize];
using (var rng = RandomNumberGenerator.Create())
{
rng.GetNonZeroBytes(buffer);
}
var sw = new Stopwatch();
sw.Start();
if (await stream.WriteAsync(buffer, 0, buffer.Length, cancellationToken) != buffer.Length)
{
return(TimeSpan.Zero);
}
var rbuf = new byte[PingSize];
if (await stream.ReadFullAsync(rbuf, cancellationToken: cancellationToken) != rbuf.Length)
{
return(TimeSpan.Zero);
}
if (!rbuf.SequenceEqual(buffer))
{
return(TimeSpan.Zero);
}
sw.Stop();
return(sw.Elapsed);
}
