docs: <T> T doExclusive(Supplier<T> supplier) {
  
          LettuceAssert.notNull(supplier, "Supplier must not be null");
  
          synchronized (this) {
  
              try {
  
                  lockWritersExclusive();
                  return supplier.get();
              } finally {
                  unlockWritersExclusive();
              }
          }
      }