Fix connection leak in post_logs

[gheel-figma]

I've noticed we have a bunch of connections stuck in CLOSE_WAIT to Statsig on our Ruby servers using this SDK. I was able to fix this by calling flush on the response from post in post_logs, which consumes the response body.

Note that I do still see some connections in CLOSE_WAIT to a Cloudflare IP address too, so there may be other cases that this doesn't fix -- however this was the most egregious in our case.

Reproducing

Run the following:

#!/usr/bin/env ruby

# Before running this, export a server key like so:
# export STATSIG_SERVER_KEY='secret-your-key-here'

require "bundler/inline"

gemfile do
  source "https://rubygems.org"
  gem "statsig"
  gem "http"
  gem "connection_pool"
end

require "openssl"
require "http"
require "statsig"

# Disable SSL verification to skip certificate CRL errors
# This causes another issue around the connection pool get deadlocking
# on my local machine, but that's a problem for another time..
HTTP.default_options = {
  ssl_context: OpenSSL::SSL::SSLContext.new.tap do |ctx|
    ctx.verify_mode = OpenSSL::SSL::VERIFY_NONE
  end
}

STATSIG_KEY = ENV["STATSIG_SERVER_KEY"]

options = StatsigOptions.new(
  { tier: "test" },
  local_mode: false,
  rulesets_sync_interval: 5,
  idlists_sync_interval: 5,
  logging_interval_seconds: 3,
  network_timeout: 2
)

Statsig.initialize(STATSIG_KEY, options)

# Generate events
test_user = StatsigUser.new({ "userID" => "test_#{Time.now.to_i}" })
puts "Generating events..."
20.times do |i|
  begin
    Statsig.check_gate(test_user, "test_gate")
    print "."
    $stdout.flush
  rescue => e
    print "Error: #{e.message}"
  end
  sleep 0.2
end

sleep 600

and then observe the connections accumulate..

$ netstat -an | grep CLOSE_WAIT

tcp4       0      0  192.168.5.133.65320    34.128.128.0.443       CLOSE_WAIT
tcp4       0      0  192.168.5.133.65232    34.128.128.0.443       CLOSE_WAIT
tcp4       0      0  192.168.5.133.65219    34.128.128.0.443       CLOSE_WAIT

[jmcfarland-figma]

I see this was merged in 2a7091f and tagged 2.8.1

Any chance this will be backported to the 2.5.x, 2.6.x and 2.7.x releases?