Interface should be consistent across platforms:
ios:

android:

Androids riotx call buttons are better positioned, IMO.
not sure, the send button is useless until something is typed
The send button while no message is in the field will most likely eventually be replaced when voice messages #29 are being implemented
If so, then I'm on your side (:
Most helpful comment
The send button while no message is in the field will most likely eventually be replaced when voice messages #29 are being implemented