@java.lang.Override
    public com.google.protobuf.Duration getHeartbeatInterval() {
      return heartbeatInterval_ == null
          ? com.google.protobuf.Duration.getDefaultInstance()
          : heartbeatInterval_;
    }
<pre>
The maximum duration of server silence before the client determines the
server unreachable.

The client must either receive a `Packet` or a heart beat message before
this duration expires; otherwise, the client will automatically cancel
the current connection and retry.
</pre>

<code>.google.protobuf.Duration heartbeat_interval = 5;</code>

@return The heartbeatInterval.
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/ReceivePacketsRequest.java