NewApp create a new root command.

NewRunCmd create a command responsible for starting an Envoy process.

NewUseCmd create a command responsible for downloading and extracting Envoy.

NewValidationError generates an error with a given format string.

NewVersionsCmd returns command that lists available Envoy versions for the current platform.

NewWhichCmd create a command responsible for downloading printing the path to the Envoy binary.

ValidationError is a marker of a validation error vs an execution one.