code: public static boolean registerConnectionManager(HttpClientConnectionManager connectionManager, long maxIdleInMs) {
          if (instance == null) {
              synchronized (IdleConnectionReaper.class) {
                  if (instance == null) {
                      instance = new IdleConnectionReaper();
                      instance.start();
                  }
              }
          }
          return connectionManagers.put(connectionManager, maxIdleInMs) == null;
      }
docs: Registers the given connection manager with this reaper;
  
  @param connectionManager Connection manager to register
  @param maxIdleInMs       Max idle connection timeout in milliseconds for this connection manager.
  @return true if the connection manager has been successfully registered; false otherwise.