Using Gmail in Safari on your iPhone gives you access to fast search, conversation view, stars, labels, and more. But it’s sometimes frustrating not knowing whether your email has been sent or whether your phone has a functioning internet connection at all. To address this, we recently introduced the “connection bar.”
The connection bar appears at the bottom of the screen when needed to give you the info you want— and then gets out of the way.
New connection bar in Gmail for iPhone - Official Gmail Blog