Need to clarify how a QUIC server specifies support for early data

I am reading the changes in Pr #618 and #619, and I wonder whether that changes how a QUIC server should be programmed to not offer support for 0RTT, e.g., because the security analysis of the application forbids 0RTT. The QUIC server declares support for 0RTT by setting the element `max_early_data_size` of `struct st_ptls_context_t` to `UINT32_MAX`. Do I understand correctly that setting `max_early_data_size` to zero will cause the tickets to not include the early data size extension?

Start by reading PRs #618 and #619, then inspect the declaration and uses of max_early_data_size in struct st_ptls_context_t. Trace how ticket extensions are generated when the value is zero or UINT32_MAX, and document the server configuration needed to disable 0RTT support.

Written by the indexing model from the issue text.