Imports of package overrides

PathSynopsis
contextPackage context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes.
errorsPackage errors implements functions to manipulate errors.
github.com/distribution/referencePackage reference provides a general type to represent any way of referencing images within the registry.
github.com/moby/buildkit/exporter
github.com/moby/buildkit/exporter/containerimage/exptypes
stringsPackage strings implements simple functions to manipulate UTF-8 encoded strings.