+
+/* Filter context
+ */
+
+__attribute__((nonnull))
+void filter_context_prepare(filter_context_t *context, void* qctx);
+
+__attribute__((nonnull))
+void filter_context_wipe(filter_context_t *context);
+
+__attribute__((nonnull))
+void filter_post_async_result(filter_context_t *context, filter_result_t result);
+