[Dovecot] Does dovecot proxy support message caching?

For example, say the connection between the user and the dovecot proxy is fast/cheap, but the connection from the proxy to the dovecot imap backend server is costly. is there a way to set up the proxy to cache messages to allow faster loading? if so, does it have different levels of caching (full message, headers only, etc)?

I'm using dovecot 2.0.9 for both the proxy and the imap backend.

if not, is there something that can work with dovecot to allow this?

Thanks!