http://www.opensips.org/html/docs/modules/1.11.x/rr.html#loose-route-id

1.5.2.  record_route() and record_route(string)

The function adds a new Record-Route header field. The header field will be inserted in the message before any other Record-Route header fields.

If any string is passed as parameter, it will be appended as URI parameter to the Record-Route header. The string must follow the“;name=value” scheme and it may contain pseudo-variables.

This function can be used from REQUEST_ROUTE, BRANCH_ROUTE and FAILURE_ROUTE.

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record_route();
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