code: func (r *runtimeVM) SignalContainer(c *Container, sig syscall.Signal) error {
  	logrus.Debug("runtimeVM.SignalContainer() start")
  	defer logrus.Debug("runtimeVM.SignalContainer() end")
  
  	// Lock the container
  	c.opLock.Lock()
  	defer c.opLock.Unlock()
  
  	return r.kill(r.ctx, c.ID(), "", sig, true)
  }
docs: // SignalContainer sends a signal to a container process.