code: func (ps *Store) RegisterRuntimeOpt(cap string, opts ...SpecOpt) {
  	ps.Lock()
  	defer ps.Unlock()
  	typ := pluginType(cap)
  	ps.specOpts[typ] = append(ps.specOpts[typ], opts...)
  }
docs: // RegisterRuntimeOpt stores a list of SpecOpts for the provided capability.
  // These options are applied to the runtime spec before a plugin is started for the specified capability.