Imports of extendedtask command

PathSynopsis
contextPackage context defines the Context type, which carries deadlines, cancellation signals, and other request-scoped values across API boundaries and between processes.
fmtPackage fmt implements formatted I/O with functions analogous to C's printf and scanf.
github.com/Microsoft/hcsshim/internal/extendedtaskCode generated by protoc-gen-go-ttrpc.
github.com/Microsoft/hcsshim/internal/shimdiagCode generated by protoc-gen-go-ttrpc.
github.com/urfave/cliPackage cli provides a minimal framework for creating and organizing command line Go applications.
osPackage os provides a platform-independent interface to operating system functionality.