Freetype Cache

Hello,

I have a question related to freetype cache subsystem.

I read in the documentation that it flushes the previous nodes and makes
the room for the new ones after the maximum nodes has reached.
Is there a timeout factor associated to the glyph data in cache? For eg. If
a glyph is not in-use for a long time then is the data of that that glyph
getting flushed out after a particular time span?
I did not read this in the documentation but just want to be double sure
about the lifetime of the data in the cache.

Thank You,
Tulsi Amin