if err != nil {
			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
			return
		}

		response := generateCopyObjectPartResponse(partInfo.ETag, partInfo.LastModified)
		encodedSuccessResponse := encodeResponse(response)

		// Write success response.
		writeSuccessResponseXML(w, encodedSuccessResponse)
		return
	}

		ETag:         "\"" + etag + "\"",
		LastModified: amztime.ISO8601Format(lastModified.UTC()),
	}
}

// generates CopyObjectPartResponse from etag and lastModified time.
func generateCopyObjectPartResponse(etag string, lastModified time.Time) CopyObjectPartResponse {
	return CopyObjectPartResponse{
		ETag:         "\"" + etag + "\"",
		LastModified: amztime.ISO8601Format(lastModified.UTC()),
	}
}