Marks the present position in the stream. Subsequent calls to reset() will attempt to reposition the stream to this point. Not all character-input streams support the mark() operation. LUCENENET specific. Moved here from the Java Reader class so it can be overridden to provide reader buffering.
Limit on the number of characters that may be read while still preserving the mark. After
/// reading this many characters, attempting to reset the stream may fail.