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: provider.go
    path of file: ./repos/sliver/vendor/github.com/aws/aws-sdk-go-v2/credentials/processcreds
    
    the code of the file until where you have to start completion: package processcreds

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"os"
	"os/exec"
	"runtime"
	"time"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/internal/sdkio"
)

const (
	// ProviderName is the name this credentials provider will label any
	// returned credentials Value with.
	ProviderName = `ProcessProvider`

	// Defau
    
func (b DefaultNewCommandBuilder) NewCommand(ctx context.Context) (*exec.Cmd, error) {
	var cmdArgs []string
	if runtime.GOOS == "windows" {
		cmdArgs = []string{"cmd.exe", "/C"}
	} else {
		cmdArgs = []string{"sh", "-c"}
	}

	if len(b.Args) == 0 {
		return nil, &ProviderError{
			Err: fmt.Errorf("failed to prepare command: command must not be empty"),
		}
	}

	cmdArgs = append(cmdArgs, b.Args...)
	cmd := exec.CommandContext(ctx, cmdArgs[0], cmdArgs[1:]...)
	cmd.Env = os.Environ()

	cmd.Stderr = os.Stderr // display stderr on console for MFA
	cmd.Stdin = os.Stdin   // enable stdin for MFA

	return cmd, nil
}