code: public final boolean cancel(final int id, final boolean mayInterrupt) {
          //noinspection SimplifiableIfStatement
          if (mUntaggedRequests.contains(id) || mTaggedRequests.containsValue(id)) {
              return RunningOperationStorage.getInstance().cancel(id, mayInterrupt);
          } else {
              return false;
          }
      }
docs: Cancels operation launch by its id. May not physically kill the background thread, but it is
  guaranteed that the result of the operation will not be delivered to any ServiceConnector.
  
  @param id           an id of the operation launch that should be cancelled
  @param mayInterrupt {@code true} if threads executing operations task should be interrupted;
  otherwise, in-progress tasks are allowed to complete
  @return {@code false} if the task could not be cancelled, typically because it has already
  completed normally; {@code true} otherwise
  @see #invoke(ChronosOperation, boolean)
  @see #invoke(ChronosOperation, String, boolean)
  @see #cancel(String, boolean)
  @see Chronos#cancelAll(boolean)