You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: engine.go
    path of file: ./repos/manba/pkg/plugin
    
    the code of the file until where you have to start completion: package plugin

import (
	"fmt"
	"net/http"
	"time"

	"github.com/fagongzi/gateway/pkg/filter"
	"github.com/fagongzi/gateway/pkg/pb/metapb"
	"github.com/fagongzi/log"
)

// Engine plugin engine
type Engine struct {
	filter.BaseFilter

	name       string
	enable     bool
	applied    []*Runtime
	lastActive time.Time
}

// NewEngine returns a plugin engine
func NewEngine(enable bool, name string) *
    
func (eng *Engine) Post(c filter.Context) (int, error) {
	if !eng.enable {
		return eng.BaseFilter.Post(c)
	}

	eng.lastActive = time.Now()

	if len(eng.applied) == 0 {
		return eng.BaseFilter.Post(c)
	}

	rc := acquireContext()
	rc.delegate = c

	l := len(eng.applied)
	for i := l - 1; i >= 0; i-- {
		rt := eng.applied[i]

		statusCode, err := rt.Post(rc)
		if nil != err {
			releaseContext(rc)
			return statusCode, err
		}

		if statusCode == filter.BreakFilterChainCode {
			releaseContext(rc)
			return statusCode, err
		}
	}

	releaseContext(rc)
	return http.StatusOK, nil
}