func (s Subject) SetUseragent(useragent string) {
	s.payload.Add(USERAGENT, NewString(useragent))
}
SetUseragent adds a useragent to the key-value store.
package tracker
type Subject struct {
	payload Payload
}
func InitSubject() *Subject {
	return &Subject{payload: *InitPayload()}
}
func (s Subject) Get() map[string]string {
	return s.payload.Get()
}
func (s Subject) SetUserId(userId string) {
	s.payload.Add(UID, NewString(userId))
}
func (s Subject) SetScreenResolution(width int, height int) {
	s.payload.Add(RESOLUTION, NewString(IntToString(width)+"x"+IntToString(height)))
}
func (s Subject) SetViewPort(width int, height int) {
	s.payload.Add(VIEWPORT, NewString(IntToString(width)+"x"+IntToString(height)))
}
func (s Subject) SetColorDepth(depth int) {
	s.payload.Add(COLOR_DEPTH, NewString(IntToString(depth)))
}
func (s Subject) SetTimeZone(timezone string) {
	s.payload.Add(TIMEZONE, NewString(timezone))
}
func (s Subject) SetLanguage(language string) {
	s.payload.Add(LANGUAGE, NewString(language))
}
func (s Subject) SetIpAddress(ipAddress string) {
	s.payload.Add(IP_ADDRESS, NewString(ipAddress))
}