What are the functional and semantic differences between making a `Composable` lambda `nullable` and...

# compose

[Yang]

What are the functional and semantic differences between making a Composable lambda nullable and assigning null as the default value VS using {} as the default value?

[Radoslaw Juszczyk]

with {} you cannot do this:

if (navigationIcon == null) {
    Spacer(TitleInsetWithoutIcon)
}

and

if (navigationIcon != {}) {
    Spacer(TitleInsetWithoutIcon)
}

would not work

[Yang]

thanks!