src/it/unimi/dsi/fastutil/io/InspectableFileCachedInputStream.java
public void truncate(final long size) throws FileNotFoundException, IOException {
		fileChannel.truncate(Math.max(size, writePosition));
	}
public void truncate(final long size) throws FileNotFoundException, IOException {
		fileChannel.truncate(Math.max(size, writePosition));
	}
Truncates the overflow file to a given size if possible.

@param size the new size; the final size is the maximum between the current write position (i.e., the length
of the represented stream minus the length of the inspection buffer) and this value.