envflag.go
func UintVar(p *uint, name string, value uint, usage string) {
	EnvironmentFlags.UintVar(p, name, value, usage)
}
func UintVar(p *uint, name string, value uint, usage string) {
	EnvironmentFlags.UintVar(p, name, value, usage)
}
// UintVar defines a uint flag with specified name, default value, and
// usage string.  The argument p points to a uint variable in which to
// store the value of the flag.