System.Net.Security.SslStreamInternal.StartFrameHeader C# (CSharp) Method

        private int StartFrameHeader(byte[] buffer, int offset, int count, AsyncProtocolRequest asyncRequest)
        {
            int readBytes = 0;

            //
            // Always pass InternalBuffer for SSPI "in place" decryption.
            // A user buffer can be shared by many threads in that case decryption/integrity check may fail cause of data corruption.
            //

            // Reset internal buffer for a new frame.
            EnsureInternalBufferSize(0, SecureChannel.ReadHeaderSize);

            if (asyncRequest != null)
            {
                asyncRequest.SetNextRequest(InternalBuffer, 0, SecureChannel.ReadHeaderSize, s_readHeaderCallback);
                _reader.AsyncReadPacket(asyncRequest);

                if (!asyncRequest.MustCompleteSynchronously)
                {
                    return 0;
                }

                readBytes = asyncRequest.Result;
            }
            else
            {
                readBytes = _reader.ReadPacket(InternalBuffer, 0, SecureChannel.ReadHeaderSize);
            }

            return StartFrameBody(readBytes, buffer, offset, count, asyncRequest);
        }