Switch DeferConnectionReset default value to true.

There have been a number of bug reports about connection pool exhaustion with the previous value of 'false' that this setting needs additional testing before it can be on by default.

Author: bgrainger

docs/content/connection-options.md

@@ -191,8 +191,8 @@ Connection pooling is enabled by default. These options are used to configure it
   </tr>
   <tr id="DeferConnectionReset">
     <td>Defer Connection Reset, DeferConnectionReset</td>
-    <td><code>false</code></td>
-    <td>If <code>true</code>, the connection state is not reset until the connection is retrieved from the pool. This was the default behaviour before MySqlConnector 1.3. The default value of <code>false</code> resets connections in the background after they’re closed which makes opening a connection faster, and releases server resources sooner.</td>
+    <td><code>true</code></td>
+    <td>If <code>true</code>, the connection state is not reset until the connection is retrieved from the pool. The experimental value of <code>false</code> resets connections in the background after they’re closed which can make opening a connection faster, and releases server resources sooner; however, there are reports of connection pool exhaustion when using this value.</td>
   </tr>
   <tr id="MaxPoolSize">
     <td>Maximum Pool Size, Max Pool Size, MaximumPoolsize, maxpoolsize</td>

src/MySqlConnector/MySqlConnectionStringBuilder.cs

@@ -643,7 +643,7 @@ static MySqlConnectionStringOption()
 
 			AddOption(DeferConnectionReset = new(
 				keys: new[] { "Defer Connection Reset", "DeferConnectionReset" },
-				defaultValue: false));
+				defaultValue: true));
 
 			AddOption(ConnectionIdlePingTime = new(
 				keys: new[] { "Connection Idle Ping Time", "ConnectionIdlePingTime" },

tests/MySqlConnector.Tests/MySqlConnectionStringBuilderTests.cs

@@ -36,7 +36,7 @@ public void Defaults()
 			Assert.False(csb.ConnectionReset);
 #else
 			Assert.True(csb.ConnectionReset);
-			Assert.False(csb.DeferConnectionReset);
+			Assert.True(csb.DeferConnectionReset);
 #endif
 			Assert.Equal(15u, csb.ConnectionTimeout);
 			Assert.False(csb.ConvertZeroDateTime);