+=item C<layout>
+
+Set and retrieve the layout object for the current request. Must be an instance
+of L<SL::Layout::Base>. Defaults to an instance of L<SL::Layout::None>.
+
+For more information about layouts, see L<SL::Layout::Dispatcher>.
+
+=item C<cache $topic[, $default ]>
+
+Caches an item for the duration of the request. C<$topic> must be an
+index name referring to the thing to cache. It is used for retrieving
+it later on. If C<$topic> doesn't start with C<::> then the caller's
+package name is prepended to the topic. For example, if the a from
+package C<SL::StuffedStuff> calls with topic = C<get_stuff> then the
+actual key will be C<::SL::StuffedStuff::get_stuff>.
+
+If no item exists in the cache for C<$topic> then it is created and
+its initial value is set to C<$default>. If C<$default> is not given
+(undefined) then a new, empty hash reference is created.
+
+Returns the cached item.
+
+=item C<post_data>
+
+If the client sends data in the request body with the content type of
+either C<application/json> or C<multipart/form-data>, the content will
+be stored in the global request object, too. It can be retrieved via
+the C<post_data> function.
+
+For content type C<multipart/form-data> the same data is additionally
+stored in the global C<$::form> instance, potentially overwriting
+parameters given in the URL. This is done primarily for compatibility
+purposes with existing code that expects all parameters to be present
+in C<$::form>.
+
+For content type C<application/json> the data is only available in
+C<$::request>. The reason is that the top-level data in a JSON
+documents doesn't have to be an object which could be mapped to the
+hash C<$::form>. Instead, the top-level data can also be an
+array. Additionally keeping the namespaces of URL and POST parameters
+separate is cleaner and allows for fewer accidental conflicts.
+