Programmatically by using sharepoint clinet object model how to copy a file from one sharepoint 2013 site to another sharepoint 2013 site with preserving its metadata like Created By, Modified By like properties?

Hi can anyone tell me how to programmatically copy a file from one sharepoint 2013 site to another sharepoint 2013 site with preserving its metadata like Created By, Modified By properties by using sharepoint client object model only?