Wiping the mailbox can cause deadlock

It seems that there is the possibility for a deadlock when a database write is performed while the mailbox starts wiping.

Example:

class DeadlockTest : IntegrationTest() {

    @Test
    fun test() {
        Thread {
            db.dropAllTablesAndClose()
        }.start()
        Thread {
            addOwnerToken()
        }.start()
    }

}