Memcached lru_crawler metadump doesn't returns END as response

We are currently working on getting all the keys in Memcached through:

lru_crawler metadump all

For this implementation, we are expecting END or OK at the end of result.

But Memcached doesn’t return any response code after the end of data. It just simply returns the metadata.

lru_crawler metadump 1
key=key exp=-1 la=1588598718 cas=1 fetch=no cls=1 size=80

We are using Memcached version 1.4.33.

Is there any configuration that we need to set up for this to return a response code at the end (or) Is there any way that we can find the end of metadump result other than END or OK?

Thanks in advance.