IOUtils for non-blocking generic socket connect #336

Job	Run time
Apache2 tests on Linux	2m 27s
C++ tests on Linux	1m 51s
C++ tests on macOS	4m 32s
Apache2 tests on macOS	3m 24s
Homebrew packaging tests	5m 45s
Nginx tests on Linux	2m 33s
Nginx dynamic module tests on Linux	1m 26s
Node.js tests on Linux	22s
Nginx tests on macOS	2m 44s
Nginx dynamic module tests on macOS	1m 8s
Node.js tests on macOS	28s
Ruby tests on Linux	1m 25s
Ruby tests on macOS	1m 7s
Source packaging tests	30s
Passenger Standalone tests on Linux	5m 20s
Passenger Standalone tests on macOS	11s
	35m 13s

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