Adds data to the post body from a file.
Appends to postBody when shouldStreamPostDataFromDisk is set to false, or writes to postBodyWriteStream when set to true. Usage NSString *documentsDirectory = [NSHomeDirectory() stringByAppendingPathComponent:"Documents"]; NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"uploadData.xml"]; ODPRequest *request=[ODPRequest requestWithURL:[NSURL URLWithString:endpointUrl]]; [request setUsername:"supuser"]; [request setPassword:@"s3puser"]; [request setRequestMethod:@"POST"]; [request appendPostDataFromFile:filePath]; [request startSynchronous];