KeyboardSpacer = () => (
  Platform.OS === 'ios' ? <KeyboardSpacerIOS /> : null
)
On iOS, the software keyboard covers the screen by default.
This is not desirable if there are TextInputs near the bottom of the screen -
they would be covered by the keyboard and the user cannot see what they
are typing.
To get around this problem, place a `<KeyboardSpacer />` at the bottom
of the screen, after your TextInputs. The keyboard spacer has size 0 and
when the keyboard is shown it will grow to the same size as the keyboard,
shifting all views above it and therefore making them visible.

On Android, this component is not needed because resizing the UI when
the keyboard is shown is supported by the OS.
Simply set the `android:windowSoftInputMode="adjustResize"` attribute
on the <activity> element in your AndroidManifest.xml.

How is this different from KeyboardAvoidingView?
The KeyboardAvoidingView doesn't work when used together with
a ScrollView/ListView.