Add `AllSettled` and `MergeSettled` APIs #550

Job	Run time
Test (Release, Pool_Enabled, devMode)	1s
Test (Release, Pool_Enabled, devMode)	1h 6m 17s
Test (Release, Pool_Enabled, userMode)	1s
Test (Release, Pool_Enabled, userMode)	56m 0s
Test (Release, Pool_Disabled, devMode)	1s
Test (Release, Pool_Disabled, devMode)	1h 6m 37s
Test (Release, Pool_Disabled, userMode)	1s
Test (Release, Pool_Disabled, userMode)	55m 47s
Test (Release_NoProgress, Pool_Enabled, devMode)	1s
Test (Release_NoProgress, Pool_Enabled, devMode)	48m 34s
Test (Release_NoProgress, Pool_Enabled, userMode)	1s
Test (Release_NoProgress, Pool_Enabled, userMode)	38m 56s
Test (Release_NoProgress, Pool_Disabled, devMode)	1s
Test (Release_NoProgress, Pool_Disabled, devMode)	43m 31s
Test (Release_NoProgress, Pool_Disabled, userMode)	1s
Test (Release_NoProgress, Pool_Disabled, userMode)	43m 16s
Test (Debug, Pool_Disabled, devMode)	1s
Test (Debug, Pool_Disabled, devMode)	1h 5m 46s
Test (Debug, Pool_Disabled, userMode)	1s
Test (Debug, Pool_Disabled, userMode)	1h 4m 33s
Test (Debug_NoProgress, Pool_Disabled, devMode)	1s
Test (Debug_NoProgress, Pool_Disabled, devMode)	36m 46s
Test (Debug_NoProgress, Pool_Disabled, userMode)	1s
Test (Debug_NoProgress, Pool_Disabled, userMode)	47m 23s
	10h 33m 38s

Provide feedback