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: corrector.go
    path of file: ./repos/vald/pkg/index/job/correction/usecase
    
    the code of the file until where you have to start completion: // Copyright (C) 2019-2024 vdaas.org vald team <vald@vdaas.org>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// You may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//	https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package usecase

impor
    
func (r *run) Start(ctx context.Context) (<-chan error, error) {
	log.Info("starting servers")
	ech := make(chan error, 3) //nolint:gomnd
	var oech <-chan error
	if r.observability != nil {
		oech = r.observability.Start(ctx)
	}
	sech := r.server.ListenAndServe(ctx)
	nech, err := r.corrector.StartClient(ctx)
	if err != nil {
		close(ech)
		return nil, err
	}

	r.eg.Go(safety.RecoverFunc(func() (err error) {
		defer close(ech)
		for {
			select {
			case <-ctx.Done():
				return ctx.Err()
			case err = <-oech:
			case err = <-nech:
			case err = <-sech:
			}
			if err != nil {
				select {
				case <-ctx.Done():
					return ctx.Err()
				case ech <- err:
				}
			}
		}
	}))

	// main groutine to run the job
	r.eg.Go(safety.RecoverFunc(func() (err error) {
		defer func() {
			log.Info("fiding my pid to kill myself")
			p, err := os.FindProcess(os.Getpid())
			if err != nil {
				// using Fatal to avoid this process to be zombie
				// skipcq: RVV-A0003
				log.Fatalf("failed to find my pid to kill %v", err)
				return
			}

			log.Info("sending SIGTERM to myself to stop this job")
			if err := p.Signal(syscall.SIGTERM); err != nil {
				log.Error(err)
			}
		}()

		start := time.Now()
		err = r.corrector.Start(ctx)
		if err != nil {
			log.Errorf("index correction process failed: %v", err)
			return err
		}
		end := time.Since(start)
		log.Infof("correction finished in %v", end)
		return nil
	}))
	return ech, nil
}