### Description

KEMI onsend_route is not called unless there is a placeholder/dummy routing block. ``` ## without this block, core will never call KEMI->onsend_route onsend_route { ## do nothing } ``` ### Troubleshooting

#### Reproduction 1. In KEMI create ksr_onsend_route(). Observe that this function is never invoked.

2. Add a route block: ``` onsend_route { ## do nothing } ``` Now observe, that KEMI ksr_onsend_route() is called.

#### Debugging Data

#### Log Messages

#### SIP Traffic

### Possible Solutions Not really a problem, just a surprise to the KEMI user. Possibly, document that in order for the KEMI function to be called, the configuration file needs a dummy routing block for onsend_route.

### Additional Information The reason is the following logic: onsend.h: `ret=keng->froute(orig_msg, ONSEND_ROUTE, NULL, NULL);`

This line is called only if `onsend_rt.rlist[DEFAULT_RT]` is non-NULL, but this array is initialized only if the `onsend_route` block exists.

* **Kamailio Version** - 5.1, master

* **Operating System**: Linux CentOS 7.4