How to runtime disable xDebug's var_dump and errors prettify?-Collection of common programming errors

I sometimes prefer to use

header("Content-type: text/plain");

Do not mess around with HTML. However, whenever an error occurs, or when I use var_dump(), it would issue a large HTML block to prettify the output. While it’s great in HTML context, I would like to disable it when I work in text/plain.

Is it possible to do? Runtime disable of the prettify?