code: func (l *State) Check(id types.CheckID) *structs.HealthCheck {
  	l.RLock()
  	defer l.RUnlock()
  
  	c := l.checks[id]
  	if c == nil || c.Deleted {
  		return nil
  	}
  	return c.Check
  }
docs: // Check returns the locally registered check that the
  // agent is aware of and are being kept in sync with the server