Imports of package control

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/distribution/referencePackage reference is deprecated, and has moved to github.com/distribution/reference.
github.com/moby/buildkit/api/services/control
github.com/moby/buildkit/api/types
github.com/moby/buildkit/cache/remotecache
github.com/moby/buildkit/client
github.com/moby/buildkit/control/gateway
github.com/moby/buildkit/exporter
github.com/moby/buildkit/frontend
github.com/moby/buildkit/session
github.com/moby/buildkit/session/grpchijack
github.com/moby/buildkit/solver
github.com/moby/buildkit/solver/llbsolver
github.com/moby/buildkit/solver/pb
github.com/moby/buildkit/util/throttle
github.com/moby/buildkit/worker
github.com/pkg/errorsPackage errors provides simple error handling primitives.
github.com/sirupsen/logrusPackage logrus is a structured logger for Go, completely API compatible with the standard library logger.
golang.org/x/sync/errgroupPackage errgroup provides synchronization, error propagation, and Context cancelation for groups of goroutines working on subtasks of a common task.
google.golang.org/grpcPackage grpc implements an RPC system called gRPC.
syncPackage sync provides basic synchronization primitives such as mutual exclusion locks.
timePackage time provides functionality for measuring and displaying time.