displayIntervalSeconds

The interval to wait between displaying in-app messages, in whole seconds.

Provided for Java callers, which cannot express a Duration. displayInterval is the source of truth; this reads and writes through to it.

Counterparts elsewhere in the SDK are named …Ms; this one is in seconds because the Long property it replaces was, so an existing Java call keeps its meaning. Reading it truncates a displayInterval with sub-second precision.