code: public Integer getLogicalSessionTimeoutMinutes() {
          Integer retVal = null;
          for (ServerDescription cur : getServersByPredicate(new Predicate() {
              @Override
              public boolean apply(final ServerDescription serverDescription) {
                  return serverDescription.isPrimary() || serverDescription.isSecondary();
              }
          })) {
              if (cur.getLogicalSessionTimeoutMinutes() == null) {
                  return null;
              }
              if (retVal == null) {
                  retVal = cur.getLogicalSessionTimeoutMinutes();
              } else {
                  retVal = Math.min(retVal, cur.getLogicalSessionTimeoutMinutes());
              }
          }
          return retVal;
      }
docs: Gets the logical session timeout in minutes, or null if at least one of the known servers does not support logical sessions.
  
  @return the logical session timeout in minutes, which may be null
  @mongodb.server.release 3.6
  @since 3.6