sample2.cs

async Task ProcessLinesAsync(NetworkStream stream)
{
    var buffer = new byte[1024];
    var bytesBuffered = 0;
    var bytesConsumed = 0;

    while (true)
    {
        var bytesRead = await stream.ReadAsync(buffer, bytesBuffered, buffer.Length - bytesBuffered);
        if (bytesRead == 0)
        {
            // EOF
            break;
        }
        // Keep track of the amount of buffered bytes
        bytesBuffered += bytesRead;
        
        var linePosition = -1;

        do
        {
            // Look for a EOL in the buffered data
            linePosition = Array.IndexOf(buffer, (byte)'\n', bytesConsumed, bytesBuffered - bytesConsumed);

            if (linePosition >= 0)
            {
                // Calculate the length of the line based on the offset
                var lineLength = linePosition - bytesConsumed;

                // Process the line
                ProcessLine(buffer, bytesConsumed, lineLength);

                // Move the bytesConsumed to skip past the line we consumed (including \n)
                bytesConsumed += lineLength + 1;
            }
        }
        while (linePosition >= 0);
    }
}