Get the status of a custom upload
ga_custom_upload(
  accountId,
  webPropertyId,
  customDataSourceId,
  uploadId,
  upload_object
)Account Id
Web Property Id
Custom data source Id
upload Id
A custom upload Id object. Supply this or the other arguments.
An object of class ga_custom_data_source_upload
You can supply either upload_object generated via function or ga_custom_upload_file, or make an 
Other custom datasource functions: 
ga_custom_datasource(),
ga_custom_upload_delete(),
ga_custom_upload_file(),
ga_custom_upload_list()