Summary:
As per the comments added - MyRouter setup is such that it starts inside a tupperware container together with the binary that will be using it. This means that by the time the binary wants to use the MyRouter connection the MyRouter instance might not be ready yet. In order to mitigate this effect the myrouter::Builder will attempt to make a "Select 1" query and retry it with a backoff for a max of 2 min or until the connection is actually established.
Unfortunately the `queries!` macro had to be moved inside the `macro` module in order to make it usable from inside `myrouter` module, see this: https://stackoverflow.com/questions/31103213/import-macro-from-parent-module
Reviewed By: farnz
Differential Revision: D10270464
fbshipit-source-id: 9cf6ad936a0cabd72967fb96796d4af3bab25822
