Example code for basic Call and Prepare/Flush.

Example functions for a simple Put & Get using Call(), and then for
Prepare() & Flush().

Each example is self-contained, and includes the server
setup/teardown.  This makes the code closer to what would be used in
an actual client program.

The Prepare() & Flush() is a bit long because we have to create the values
we are later scanning for.
technically one would have to check that we're not leaving the slice, for both firstKey and lastKey since numScans looks like you should be able to change it to whatever and get a running example.
It being an example, though, I think it's ok.