docs: public void setFastCatchupTimeSecs(long secondsSinceEpoch) {
          lock.lock();
          try {
              checkState(chain == null || !chain.shouldVerifyTransactions(), "Fast catchup is incompatible with fully verifying");
              fastCatchupTimeSecs = secondsSinceEpoch;
              if (downloadPeer != null) {
                  downloadPeer.setDownloadParameters(secondsSinceEpoch, bloomFilterMerger.getLastFilter() != null);
              }
          } finally {
              lock.unlock();
          }
      }