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: output.go
    path of file: ./repos/benthos/internal/impl/sftp
    
    the code of the file until where you have to start completion: package sftp

import (
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"path/filepath"
	"sync"

	"github.com/pkg/sftp"

	"github.com/benthosdev/benthos/v4/internal/codec"
	"github.com/benthosdev/benthos/v4/internal/component/output"
	"github.com/benthosdev/benthos/v4/public/service"
)

const (
	soFieldAddress     = "address"
	soFieldCredentials = "credentials"
	soFieldPath        = "path"
)

func sftpOutputSpec() *service.ConfigSpec {
	return service.NewConfigSpec().
		Beta().
		Categories("Network").
		Version("3.39.0").
		Summary(`Writes files to an SFTP server.`).
		Description(output.Description(true, false, `In order to have a different path for each object you should use function interpolations described [here](/docs/configuration/interpolation#bloblang-queries).`)).

    
func sftpOutputSpec() *service.ConfigSpec {
	return service.NewConfigSpec().
		Beta().
		Categories("Network").
		Version("3.39.0").
		Summary(`Writes files to an SFTP server.`).
		Description(output.Description(true, false, `In order to have a different path for each object you should use function interpolations described [here](/docs/configuration/interpolation#bloblang-queries).`)).
		Fields(
			service.NewStringField(soFieldAddress).
				Description("The address of the server to connect to."),
			service.NewInterpolatedStringField(soFieldPath).
				Description("The file to save the messages to on the server."),
			service.NewInternalField(codec.NewWriterDocs("codec").HasDefault("all-bytes")),
			service.NewObjectField(soFieldCredentials, credentialsFields()...).
				Description("The credentials to use to log into the target server."),
			service.NewOutputMaxInFlightField(),
		)
}