while (true)
            {
                // Read at most the number of bytes that will fit in the input buffer. The
                // return value is the actual number of bytes read, or zero if no bytes remain.
                bytesRead = stream.Read(bytes, 0, useBufferSize * 4);
                if (bytesRead == 0)
                {
                    break;
                }

                bool completed = false;
                int byteIndex = 0;
                int bytesUsed;
                int charsUsed;

                while (bytesRead > byteIndex)
                {
                    // If this is the last input data, flush the decoder's internal buffer and state.
                    bool flush = (bytesRead == 0);
                    decoder.Convert(bytes, byteIndex, bytesRead - byteIndex,
                                    chars, 0, useBufferSize, flush,
                                    out bytesUsed, out charsUsed, out completed);
                    // The conversion produced the number of characters indicated by charsUsed. Write that number
                    // of characters to our result buffer
                    result.Append(chars, 0, charsUsed);

                    // Increment byteIndex to the next block of bytes in the input buffer, if any, to convert.
                    byteIndex += bytesUsed;
                }
            } while (bytesRead != 0);