code: func FromContext(ctx context.Context, opts ...WriterOption) (Writer, bool, context.Context) {
  	v := ctx.Value(contextKey)
  	pw, ok := v.(*progressWriter)
  	if !ok {
  		if pw, ok := v.(*MultiWriter); ok {
  			return pw, true, ctx
  		}
  		return &noOpWriter{}, false, ctx
  	}
  	pw = newWriter(pw)
  	for _, o := range opts {
  		o(pw)
  	}
  	ctx = context.WithValue(ctx, contextKey, pw)
  	return pw, true, ctx
  }
docs: // FromContext returns a progress writer from a context.