Parse new NAT-based Snowflake lines
With the merge of tpo/anti-censorship/pluggable-transports/snowflake#40008 (closed), the snowflake stats file now contains new lines:
"client-restricted-denied-count" NUM NL
[At most once.]
A count of the number of times a client with a restricted or
unknown NAT type has requested a proxy from the broker but no
proxies were available, rounded up to the nearest multiple of 8.
"client-unrestricted-denied-count" NUM NL
[At most once.]
A count of the number of times a client with an unrestricted NAT
type has requested a proxy from the broker but no proxies were
available, rounded up to the nearest multiple of 8.
"snowflake-ips-nat-restricted" NUM NL
[At most once.]
A count of the total number of unique IP addresses of snowflake
proxies that have a restricted NAT type.
"snowflake-ips-nat-unrestricted" NUM NL
[At most once.]
A count of the total number of unique IP addresses of snowflake
proxies that have an unrestricted NAT type.
"snowflake-ips-nat-unknown" NUM NL
[At most once.]
A count of the total number of unique IP addresses of snowflake
proxies that have an unknown NAT type.