There has been issues reported by GW users that Evolution hangs/suspends for a while when composing mails. We weren't able to reproduce the issue and respective gdb traces didn't give enough information. Lately, I started hibernating my laptop and when I resume from hibernation, I noticed that EDS started taking 100% CPU and when gdb is attached to the process... voila!!!.. EDS was running with 264 threads and most of it are waiting to update GW addressbook and rest are waiting to update GW calendars.
A little further investigation revealed that it was because of the combination of g_timeout_add()+hibernation. GLib stores the last processed time for g_timeout_add and when hibernated, the memory image is stored and restored, when resumed from hibernation. When restored, callbacks registered with g_timeout_add() gets called - as the difference in time during hibernation and resume satisfies the g_timeout_add() timeout value and that too in multiples of 100. Harinath (of Mono fame) helped me understand the GLib part and the fixes have gone in for GW and webcal provider.