code: private boolean executeWrites(List<Write> toExecute) {
          log.debug("{}: Executing {} writes.", this.traceObjectId, toExecute.size());
          for (int i = 0; i < toExecute.size(); i++) {
              Write w = toExecute.get(i);
              try {
                  // Record the beginning of a new attempt.
                  int attemptCount = w.beginAttempt();
                  if (attemptCount > this.config.getMaxWriteAttempts()) {
                      // Retried too many times.
                      throw new RetriesExhaustedException(w.getFailureCause());
                  }
  
                  // Invoke the BookKeeper write.
                  w.getWriteLedger().ledger.asyncAddEntry(w.data.array(), w.data.arrayOffset(), w.data.getLength(), this::addCallback, w);
              } catch (Throwable ex) {
                  // Synchronous failure (or RetriesExhausted). Fail current write.
                  boolean isFinal = !isRetryable(ex);
                  w.fail(ex, isFinal);
  
                  // And fail all remaining writes as well.
                  for (int j = i + 1; j < toExecute.size(); j++) {
                      toExecute.get(j).fail(new DurableDataLogException("Previous write failed.", ex), isFinal);
                  }
  
                  return false;
              }
          }
  
          // Success.
          return true;
      }
docs: Executes the given Writes to BookKeeper.
  
  @param toExecute The Writes to execute.
  @return True if all the writes succeeded, false if at least one failed (if a Write failed, all subsequent writes
  will be failed as well).