In many of my projects, I turn off the URL print statements with:

# Remove URL route logging
logging.getLogger('werkzeug').setLevel(logging.ERROR)

Should we do the same in Dash? Some thoughts:

• If we do it, we'll need a way to make it overridable in case users actually do want it. That is, placing it in run_server might be too late.
• Sometimes I find these statements useful when the dash is autorestarting and I'm refreshing the page. When the server has finished restarting, I'll see a flurry of print statements and I know that I'm ready to check out the web site. Of course, hopefully hot-reloading solves this in a more elegant way.
• The URLs themselves aren't that useful since all of the callbacks are just POST /_dash-update-component. We could make more useful debugging statements like -> 'my-graph.figure start', -> 'my-graph.figure.end` as part of a default dev tools / environment thing