const runtime.traceBlockSync

3 uses

	runtime (current package)
		sema.go#L192: 		goparkunlock(&root.lock, reason, traceBlockSync, 4+skipframes)
		traceruntime.go#L95: 	traceBlockSync
		traceruntime.go#L115: 	traceBlockSync:               "sync",

The pages are generated with Golds v0.7.6. (GOOS=linux GOARCH=amd64)