docs: public long getSecondsUntilExpiry(Sha256Hash id) {
          lock.lock();
          try {
              final Set<StoredClientChannel> setChannels = mapChannels.get(id);
              final long nowSeconds = Utils.currentTimeSeconds();
              int earliestTime = Integer.MAX_VALUE;
              for (StoredClientChannel channel : setChannels) {
                  synchronized (channel) {
                      if (channel.expiryTimeSeconds() > nowSeconds)
                          earliestTime = Math.min(earliestTime, (int) channel.expiryTimeSeconds());
                  }
              }
              return earliestTime == Integer.MAX_VALUE ? 0 : earliestTime - nowSeconds;
          } finally {
              lock.unlock();
          }
      }