document interval and timeout

exporter/loadbalancingexporter/README.md

@@ -19,7 +19,11 @@ Refer to [config.yaml](./testdata/config.yaml) for detailed examples on using th
 * The `otlp` property configures the template used for building the OTLP exporter. Refer to the OTLP Exporter documentation for information on which options are available. Note that the `endpoint` property should not be set and will be overridden by this exporter with the backend endpoint.
 * The `resolver` accepts either a `static` node, or a `dns`. If both are specified, `dns` takes precedence.
 * The `hostname` property inside a `dns` node specifies the hostname to query in order to obtain the list of IP addresses.
-* The `dns` node also accepts an optional property `port` to specify the port to be used for exporting the traces to the IP addresses resolved from `hostname`. If `port` is not specified, the default port 4317 is used.
+* The `dns` node also accepts the following optional properties:
+  * `hostname` DNS hostname to resolve. 
+  * `port` port to be used for exporting the traces to the IP addresses resolved from `hostname`. If `port` is not specified, the default port 4317 is used.
+  * `interval` resolver interval in go-Duration format, e.g. `5s`, `1d`, `30m`. If not specified, `5s` will be used.
+  * `timeout` resolver timeout in go-Duration format, e.g. `5s`, `1d`, `30m`. If not specified, `1s` will be used.
 
 
 Simple example