Copies from S3 to the local file system.  
            If the file already exists on the local file system and overwrite is set to false than an ArgumentException is thrown.
            
 Return Value
 Return ValueFileInfo for the local file where file is copied to.
 Exceptions
 Exceptions| Exception | Condition | 
|---|---|
| IOException | If the file already exists locally and overwrite is set to false. | 
| WebException | |
| AmazonS3Exception |