Change ConnectionPool to not use an iterators for .empty! and .clear! (#3021)

Author: jterapin

gems/aws-sdk-core/CHANGELOG.md

@@ -1,6 +1,8 @@
 Unreleased Changes
 ------------------
 
+* Issue - Fix `ConnectionPool` for `.empty!` and `.clear!` since it prevented adding a new key from being added to the pool (#3020).
+
 3.196.0 (2024-05-13)
 ------------------
 

gems/aws-sdk-core/lib/seahorse/client/net_http/connection_pool.rb

@@ -138,9 +138,7 @@ def clean!
         # @return [nil]
         def empty!
           @pool_mutex.synchronize do
-            @pool.each_pair do |endpoint,sessions|
-              sessions.each(&:finish)
-            end
+            @pool.values.flatten.map(&:finish)
             @pool.clear
           end
           nil
@@ -308,7 +306,7 @@ def start_session endpoint
         # @note **Must** be called behind a `@pool_mutex` synchronize block.
         def _clean
           now = Aws::Util.monotonic_milliseconds
-          @pool.each_pair do |endpoint,sessions|
+          @pool.values.each do |sessions|
             sessions.delete_if do |session|
               if session.last_used.nil? or now - session.last_used > http_idle_timeout * 1000
                 session.finish