sample3.cs

async Task ProcessLinesAsync(NetworkStream stream)
{
    byte[] buffer = ArrayPool<byte>.Shared.Rent(1024);
    var bytesBuffered = 0;
    var bytesConsumed = 0;

    while (true)
    {
        // Calculate the amount of bytes remaining in the buffer
        var bytesRemaining = buffer.Length - bytesBuffered;

        if (bytesRemaining == 0)
        {
            // Double the buffer size and copy the previously buffered data into the new buffer
            var newBuffer = ArrayPool<byte>.Shared.Rent(buffer.Length * 2);
            Buffer.BlockCopy(buffer, 0, newBuffer, 0, buffer.Length);
            // Return the old buffer to the pool
            ArrayPool<byte>.Shared.Return(buffer);
            buffer = newBuffer;
            bytesRemaining = buffer.Length - bytesBuffered;
        }

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