Imports of package builder

PathSynopsis
contextPackage context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes.
github.com/docker/docker/api/types/backendPackage backend includes types to send information to server backends.
github.com/docker/docker/api/types/container
github.com/docker/docker/container
github.com/docker/docker/image
github.com/docker/docker/layerPackage layer is package for managing read-only and read-write mounts on the union file system driver.
github.com/opencontainers/go-digestPackage digest provides a generalized type to opaquely represent message digests and their operations within the registry.
github.com/opencontainers/image-spec/specs-go/v1
ioPackage io provides basic interfaces to I/O primitives.