Allowed number of HTTP/2 continuation frames

[mkauf]

nghttp2 1.61.0 limits the number of HTTP/2 continuation frames and provides the new function nghttp2_option_set_max_continuations(). By default, 8 continuation frames are allowed.

Envoy increased the value to 1024 in this commit: envoyproxy/envoy@7d0c522

Are 8 HTTP/2 continuation frames enough? Should the value be part of the configuration, or could mod_h2 calculate a value based on LimitRequestLine, LimitRequestFields and LimitRequestFieldSize ?

[icing]

Since mod_h2 now RSTs the stream after 100 incoming headers exceeding the limit, we could safely raise the number of frames. Some people, I learned, work with really huge headers.