Document reconnect_after option in net.box:new

[mejedi]

With reconnect_after <timeout> option, net.box instance will automatically reconnect any time the connection is broken or if a connection attempt fails. The number of retries is unlimited. Once a connection is explicitly closed (or garbage-collected), reconnects stop.

Assume application maintains a connection to server X. With reconnect_after, transient network failures become transparent to the application. Reconnect happens automatically in the background and queries/requests that suffered due to connectivity loss are transparently retried.

In the presense of reconnect_after, wait_connected ignores transient failures. The wait completes once the connection is established or is closed explicitly.