Imports of package sync

PathSynopsis
internal/racePackage race contains helper functions for manually instrumenting code for the race detector.
internal/syncPackage sync provides basic synchronization primitives such as mutual exclusion locks to internal packages (including ones that depend on sync).
runtimePackage runtime contains operations that interact with Go's runtime system, such as functions to control goroutines.
sync/atomicPackage atomic provides low-level atomic memory primitives useful for implementing synchronization algorithms.
unsafePackage unsafe contains operations that step around the type safety of Go programs.