C# 클래스 XtermSharp.ReadingBuffer

Because data might not be complete, we need to put back data that we read to process on a future read. To prepare for reading, on every call to parse, the prepare method is given the new buffer to read from. the `hasNext` describes whether there is more data left on the buffer, and `bytesLeft` returnes the number of bytes left. The `getNext` method fetches either the next value from the putback buffer, or when it is empty, it returns it from the buffer that was passed during prepare. Additionally, the terminal parser needs to reset the parser state on demand, and that is surfaced via reset