setProps - depends on reading the last reconciled props from the current reconciled state of the app, at the time of the call. It also depends on an object that doesn't necessarily need to be there outside reconciliation. This is unlike setState, which is state that needs to be there. setState is queued up and merged at the time of reconciliation. Not at the time of the call. setState has a side-effect but is not a stateful nor mutative API.
isMounted - reads the current state of the tree, which may be stale if you're in a batch or reconciliation.
getDOMNode/findDOMNode - Reads the currently flushed node. This currently relies on the state of the system and that everything has flushed at this time. We could potentially do a forced render but that would still rely on the state of the system allowing us to synchronously being able to force a rerender of the system. Note: in 0.14, refs directly to DOM node will resolve to the DOM node. This allow you to get access to a node at the time of its choos
