Make global EpollRuntime independent of IORuntime
#44
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This fixes an issue where
EpollApps were hanging upon the first async I/O op.The problem was, unbeknownst to me, if you override the
runtimein anIOAppit does not get installed asIORuntime.global. BecauseEpollRuntime.globalwas working in terms ofIORuntime.global, this was causing twoEpollRuntimes to be created, with I/O callbacks registered on the the second one not used by theEpollApp. Thus, the hang.The fix is to just make the
EpollRuntime.globalcompletely independent ofIORuntime.global. There is a bit of a footgun here, since two runtimes cannot coexist in a meaningful way, but I am following the Cats Effect design choice that an overridden runtime should not replace its own global runtime.To explore this issue I created an example app and reorganized some of the test scaffolds. The example app is now run as part of the CI workflow.