Xdebug tends to slow down a lot of things. Here's a hack to unload the extension by default but load it whenever it's needed (for instance, when generating php code coverage.
Prevent Xdebug from loading by default
If you use brew to install php 7, should be here:
/usr/local/etc/php/<version>/conf.d/ext-xdebug.ini. Edit that file (replacing
<version> with whatever version of php you're using) and comment out the line that begins with
zend_extension. The code examples here assume