Prevent clients from sticking to old pools after config update (#113)

* Re-acquire pool at the beginning of Protocol loop

* Fix query router + add tests for recycling behavior

tests/ruby/Gemfile.lock

@@ -19,6 +19,7 @@ GEM
     parallel (1.22.1)
     parser (3.1.2.0)
       ast (~> 2.4.1)
+    parslet (2.0.0)
     pg (1.3.2)
     rainbow (3.1.1)
     regexp_parser (2.3.1)
@@ -35,17 +36,21 @@ GEM
     rubocop-ast (1.17.0)
       parser (>= 3.1.1.0)
     ruby-progressbar (1.11.0)
+    toml (0.3.0)
+      parslet (>= 1.8.0, < 3.0.0)
     tzinfo (2.0.4)
       concurrent-ruby (~> 1.0)
     unicode-display_width (2.1.0)
 
 PLATFORMS
+  arm64-darwin-21
   x86_64-linux
 
 DEPENDENCIES
   activerecord
   pg
   rubocop
+  toml (~> 0.3.0)
 
 BUNDLED WITH
    2.3.7