segmentFileName

Returns a file name that includes the given segment name, your own custom name and extension. The format of the filename is: (_)(.).

NOTE: . is added to the result file name only if ext is not empty.

NOTE: _ is added to the result file name only if it's not the empty string

NOTE: all custom files should be named using this method, or otherwise some structures may fail to handle them properly (such as if they are added to compound files).