code: private void readHostsToSessions(CoronaSerializer coronaSerializer)
      throws IOException {
      coronaSerializer.readField("hostsToSessions");
      // Expecting the START_OBJECT token for hostsToSessions
      coronaSerializer.readStartObjectToken("hostsToSessions");
      JsonToken current = coronaSerializer.nextToken();
  
      while (current != JsonToken.END_OBJECT) {
        String host = coronaSerializer.getFieldName();
        Set<String> sessionsSet = coronaSerializer.readValueAs(Set.class);
        hostsToSessions.put(nameToNode.get(host), sessionsSet);
        current = coronaSerializer.nextToken();
      }
    }
docs: Reads the hostsToSessions map from the JSON stream
  @param coronaSerializer The CoronaSerializer instance to be used to
  read the JSON
  @throws java.io.IOException