public static string query ()
Optional API for GIO modules to implement.
Should return a list of all the extension points that may be implemented in this module.
This method will not be called in normal use, however it may be called when probing existing modules and recording which extension points that this model is used for. This means we won't have to load and initialize this module unless its needed.
If this function is not implemented by the module the module will always be loaded, initialized and then unloaded on application startup so that it can register its extension points during init.
Note that a module need not actually implement all the extension points that query returns, since the exact list of extension may depend on runtime issues. However all extension points actually implemented must be returned by query (if defined).
When installing a module that implements query you must run gio-querymodules in order to build the cache files required for lazy loading.
Since 2.56, this function should be named `g_io_<modulename>_query`, where `modulename` is the plugin’s filename with the `lib` or `libgio` prefix and everything after the first dot removed, and with `-` replaced with `_` throughout. For example, `libgiognutls-helper.so` becomes `gnutls_helper`. Using the new symbol names avoids name clashes when building modules statically. The old symbol names continue to be supported, but cannot be used for static builds.
A null-terminated array of strings, listing the supported extension points of the module. The array must be suitable for freeing with strfreev.