Let handles be seen outside of `memfiles` module so that "updating" operations (like eg., resizing a file and re-mapping) do not need to worry about race conditions of re-opened paths, renamed parent directories and that sort of thing.  Operating directly on already open handles is both safer and more efficient than relying upon the stability of filesystem paths.
Let handles be seen outside of `memfiles` module so that "updating"
operations (like eg., resizing a file and re-mapping) do not need
to worry about race conditions of re-opened paths, renamed parent
directories and that sort of thing.  Operating directly on already
open handles is both safer and more efficient than relying upon the
stability of filesystem paths.

dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim