Need more example in Transaction Insert and Query

From this documentation, there are several transaction in ObjectBox
http://objectbox.io/documentation/transactions/

The class BoxStore offers the following methods to perform explicit transactions:
runInTx: Runs the given runnable inside a transaction.
runInReadTx: Runs the given runnable inside a read(-only) transaction. Unlike write transactions, multiple read transactions can run at the same time.
runInTxAsync: Runs the given Runnable as a transaction in a separate thread. Once the transaction completes the given callback is called (callback may be null).
callInTx: Like runInTx(Runnable), but allows returning a value and throwing an exception.

But I found little confused for runInTxAsync implementation. Any good example about how to implementation those transaction ?

Start with the transaction documentation linked in the issue and review the descriptions of runInTx, runInReadTx, runInTxAsync, and callInTx. Add clear transaction insert and query examples, including runInTxAsync, so readers can see how each method is implemented and when it completes.