TLS 1.3 Early Data (0RTT)

One of the acknowledged disadvantages of TLS for Gemini is latency.
TLS 1.3 has a feature that could mitigate this problem in some
circumstances.  To quote RFC 8470:

> TLS 1.3 [TLS13] introduces the concept of early data (also known as
> zero round-trip time (0-RTT) data).  If the client has spoken to the
> same server recently, early data allows a client to send data to a
> server in the first round trip of a connection, without waiting for
> the TLS handshake to complete.
>
> When used with HTTP [HTTP], early data allows clients to send
> requests immediately, thus avoiding the one or two round-trip delays
> needed for the TLS handshake.  This is a significant performance
> enhancement; however, it has significant limitations.
>
> The primary risk of using early data is that an attacker might
> capture and replay the request(s) it contains.

Has anyone implemented a Gemini client and/or server with support for
0-RTT data? Any thoughts on which requests can safely use it?  (For
example, would it be reasonable to allow early data for all requests
that don't use a client certificate?)

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