code: func NewHandlerRegistry(allowUnsolicitedRegistration bool) *HandlerRegistry {
  	return &HandlerRegistry{
  		handlers:                     map[string]*Handler{},
  		launching:                    map[string]*LaunchState{},
  		allowUnsolicitedRegistration: allowUnsolicitedRegistration,
  	}
  }
docs: // NewHandlerRegistry constructs a HandlerRegistry.