Text item: plain, toString, toString()?

I would like to concatenate a string with a text item. I’m not clear on whether I need to use the .toString or not. Can someone clarify which of the following is correct? I would like to learn more, so please point me to some documentation if possible on this. The Designer seems to think all 3 forms of the PARTITION1_STATUS.* are fine.

rule "Push Status"
    Item PARTITION1_STATUS changed
    var String requestToSend
    requestToSend = "" + PARTITION1_STATUS.state
    requestToSend = "" + PARTITION1_STATUS.state.toString
    requestToSend = "" + PARTITION1_STATUS.state.toString()

PARTITION1_STATUS.state is a state. As you compound this state with a string, maybe openHAB will silently turn this state into a string (but there is no guarantee for this, try it out)

PARTITION1_STATUS.state.toString is a string, this is definitely correct and the Designer will complete item.state.toStrin to item.state.toString.

I’m pretty sure that the brackets don’t make any difference, especially as there is nothing to commit.