nginx gzip_http_version pode ter HTTP 1.0 e tem suas advertências.
When HTTP version 1.0 is used, the Vary: Accept-Encoding header is not set. As
this can lead to proxy cache corruption, consider adding it with add_header.
Also note that the Content-Length header is not set when using either version.
Keepalives will therefore be impossible with version 1.0, while for 1.1 it is
handled by chunked transfers.
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