Add example output.

README.md

@@ -16,3 +16,34 @@ flag. Paths need to be comma separated.
 
 Please refer to this utility's `main()` function for a full list of
 supported command line flags.
+
+## Client statistics
+
+For clients status files, the exporter generates metrics that may look
+like this:
+
+```
+openvpn_client_auth_read_bytes_total{status_path="..."} 3.08854782e+08
+openvpn_client_post_compress_bytes_total{status_path="..."} 4.5446864e+07
+openvpn_client_post_decompress_bytes_total{status_path="..."} 2.16965355e+08
+openvpn_client_pre_compress_bytes_total{status_path="..."} 4.538819e+07
+openvpn_client_pre_decompress_bytes_total{status_path="..."} 1.62596168e+08
+openvpn_client_tcp_udp_read_bytes_total{status_path="..."} 2.92806201e+08
+openvpn_client_tcp_udp_write_bytes_total{status_path="..."} 1.97558969e+08
+openvpn_client_tun_tap_read_bytes_total{status_path="..."} 1.53789941e+08
+openvpn_client_tun_tap_write_bytes_total{status_path="..."} 3.08764078e+08
+openvpn_status_update_time_seconds{status_path="..."} 1.490092749e+09
+openvpn_up{status_path="..."} 1
+```
+
+## Server statistics
+
+For server status files (both version 2 and 3), the exporter generates
+metrics that may look like this:
+
+```
+openvpn_server_clients{status_path="..."} 5
+openvpn_server_routes{status_path="..."} 5
+openvpn_status_update_time_seconds{status_path="..."} 1.490089154e+09
+openvpn_up{status_path="..."} 1
+```