(feel free to dup if this issue has been discussed previously)
A lot of different parties -- such as Ads, frameworks etc -- are now adding mark & measure to timeline. It is spammy to receive all the marks added by everyone on the timeline.

Currently developers have to discover and maintain a list of name prefixes to ignore.
(for instance Google Ads caused some ripples with adding "goog" prefixed marks affecting large number of sites)

Instead, it would be great if marks & measures could be namespace'd and developers could subscribe to specific namespaces.

@pmeenan @paulirish @nicjansma