EFS billing for os.listdir(path), os.stat(), os.path.exists() with a small amount of transferred data

Could someone clarify how resource usage is calculated when executing an os.stat(), os.listdir() command? Specifically, I'm wondering whether the actual volume of data transferred is considered for billing purposes. How is this handled in cases where the data volume is minimal, such as when only a couple of files (totaling 100 bytes) are listed, or when only a small amount of metadata is read from a file?