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: main.go
    path of file: ./repos/protobuf/protoc-gen-go
    
    the code of the file until where you have to start completion: // Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// protoc-gen-go is a plugin for the Google protocol buffer compiler to generate
// Go code. Install it by building this program and making it accessible within
// your PATH with the name:
//
//	protoc-gen-go
//
// The 'go' suffix becomes part of the argument for the protocol compiler,
// such that it can be invoked as:
//
//	protoc --go_out=paths=source_relative:. path/to/file.proto
//
// This generates Go bindings for the protocol buffer defined by file.proto.
// With that input, the output will be written to:
//
//	path/to/file.pb.go
//
// See the README and documentation for protocol buffers to learn more:
//
//	https://developers.google.com/protocol-buffers/
package main

import (
	"flag"
	"fmt"
	"strings"

	"github.com/golang/protobuf/internal/gengogrpc"
	gengo "google.golang.org/protobuf/cmd/protoc-gen-go/internal_gengo"
	"google.golang.org/protobuf/compiler/pro
    
func main() {
	var (
		flags        flag.FlagSet
		plugins      = flags.String("plugins", "", "list of plugins to enable (supported values: grpc)")
		importPrefix = flags.String("import_prefix", "", "prefix to prepend to import paths")
	)
	importRewriteFunc := func(importPath protogen.GoImportPath) protogen.GoImportPath {
		switch importPath {
		case "context", "fmt", "math":
			return importPath
		}
		if *importPrefix != "" {
			return protogen.GoImportPath(*importPrefix) + importPath
		}
		return importPath
	}
	protogen.Options{
		ParamFunc:         flags.Set,
		ImportRewriteFunc: importRewriteFunc,
	}.Run(func(gen *protogen.Plugin) error {
		grpc := false
		for _, plugin := range strings.Split(*plugins, ",") {
			switch plugin {
			case "grpc":
				grpc = true
			case "":
			default:
				return fmt.Errorf("protoc-gen-go: unknown plugin %q", plugin)
			}
		}
		for _, f := range gen.Files {
			if !f.Generate {
				continue
			}
			g := gengo.GenerateFile(gen, f)
			if grpc {
				gengogrpc.GenerateFileContent(gen, f, g)
			}
		}
		gen.SupportedFeatures = gengo.SupportedFeatures
		return nil
	})
}