buf#duration>Duration</a></code></td><td><p>Indicates how long to keep a list before discarding it.
Typically, the TTL value should be set to noticeably longer (> 2x) than the
refresh interval to ensure continued operation in the face of transient
server outages.</p></td><td>No</td></tr><tr id=Params-caching_interval><td><code>cachingInterval</code></td><td><code><a href=https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#duration>Duration</a></code></td><td><p>Indicates the amount