let doWnloadfileurl = NSURL.fileURL(withPath:"your download path") as URL
let getobjectreq = AWSS3GetObjectRequest.init()
getobjectreq?.bucket = S3BucketName
getobjectreq?.key = "logo.png"
getobjectreq?.downloadingFileURL = doWnloadfileurl
s3.getObject(getobjectreq!).continueWith(block: { (task:AWSTask<AWSS3GetObjectOutput>) -> Any? in
if let error = task.error {
print("get object failed with error: (\(error))")
} else {
print("get object completed.")
}
return nil
}) | 
