CloseableSequence

A Sequence backed by an underlying resource (e.g., an open JDBC ResultSet) that must be released.

The resource is closed automatically when the iteration reaches the end, or when fetching the next element (i.e., Iterator.hasNext / Iterator.next) throws. It is NOT closed when your own code processing the elements throws, or when you stop iterating midway (e.g., with take or first). Unless you fully iterate the sequence, close it explicitly with close, typically via use:

client.sql { +"SELECT * FROM users" }.sequence<User>().use { seq ->
    seq.first()
}

This sequence can be iterated only once.

Like ordinary Sequences (and the underlying JDBC resources), this sequence is not thread-safe; obtain and iterate it on a single thread.