#define io_slurp(ig, datap) ((im_extt->f_io_slurp)((ig), (datap)))
#define io_glue_destroy(ig) ((im_extt->f_io_glue_destroy)(ig))
+#define i_mutex_new() ((im_extt->f_i_mutex_new)())
+#define i_mutex_destroy(m) ((im_extt->f_i_mutex_destroy)(m))
+#define i_mutex_lock(m) ((im_extt->f_i_mutex_lock)(m))
+#define i_mutex_unlock(m) ((im_extt->f_i_mutex_unlock)(m))
+
+#define im_context_slot_new(destructor) ((im_extt->f_im_context_slot_new)(destructor))
+#define im_context_slot_get(ctx, slot) ((im_extt->f_im_context_slot_get)((ctx), (slot)))
+#define im_context_slot_set(ctx, slot, value) ((im_extt->f_im_context_slot_set)((ctx), (slot), (value)))
+
#define im_push_errorf (im_extt->f_im_push_errorf)
#ifdef IMAGER_LOG