Assert on API violation

src/dbuf.c

@@ -99,7 +99,7 @@ uc_dbuf_take(DBuf *buf, size_t len)
     } else if (len < buflen) {
         buf->start = buf->start + len;
     } else {
-        //should maybe assert. This is a serious offence
+        assert(0);
         return 1;
     }