HostLivenessTracker (config-provisioning 7.525.28 API)

```
public interface HostLivenessTracker
```
Instances of this are used to keep track of (notify and query) which hosts are currently connected to the config system.

Author:

bratseth

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Optional<Instant>`	`lastRequestFrom(String hostname)`	Returns the epoch timestamp of the last request received from the given hostname, or empty if there is no memory of this host making a request
`void`	`receivedRequestFrom(String hostname)`	Called each time a config request is received from a client

- Method Detail
  - receivedRequestFrom
```
void receivedRequestFrom(String hostname)
```
    Called each time a config request is received from a client
  - lastRequestFrom
```
Optional<Instant> lastRequestFrom(String hostname)
```
    Returns the epoch timestamp of the last request received from the given hostname, or empty if there is no memory of this host making a request