Resolve "Ensure blobstore WalkFn is thread safe"
requested to merge 4-ensure-blobstore-walkfn-is-thread-safe into 3-optimize-the-s3-storage-driver-s-walk-function
This MR address issues #4 (closed) and #7 (closed) by ensuring thread safe map access in garbage_collect_test.go. According to GoCallers, with this MR all functions ultimately passed to Walk in both blobstore and linkedblobstore should be thread-safe.
Edited by Hayley Swimelar