Create Action upfront to reduce temporary Action allocations.

This reduces allocations in the "ManyRowsNewSync" scenario by 19%.

Author: bgrainger

src/MySqlConnector/MySqlClient/CommandExecutors/TextCommandExecutor.cs

@@ -51,7 +51,7 @@ public virtual async Task<DbDataReader> ExecuteReaderAsync(string commandText, M
 			CommandBehavior behavior, IOBehavior ioBehavior, CancellationToken cancellationToken)
 		{
 			cancellationToken.ThrowIfCancellationRequested();
-			using (cancellationToken.Register(m_command.Cancel))
+			using (cancellationToken.Register(m_command.CancelAction))
 			{
 				m_command.Connection.Session.StartQuerying(m_command);
 				m_command.LastInsertedId = -1;

src/MySqlConnector/MySqlClient/MySqlCommand.cs

@@ -37,6 +37,7 @@ public MySqlCommand(string commandText, MySqlConnection connection, MySqlTransac
 			DbTransaction = transaction;
 			m_parameterCollection = new MySqlParameterCollection();
 			CommandType = CommandType.Text;
+			CancelAction = Cancel;
 		}
 
 		public new MySqlParameterCollection Parameters
@@ -50,6 +51,8 @@ public MySqlCommand(string commandText, MySqlConnection connection, MySqlTransac
 
 		public override void Cancel() => Connection.Cancel(this);
 
+		internal Action CancelAction { get; private set; }
+
 		public override int ExecuteNonQuery() =>
 			ExecuteNonQueryAsync(IOBehavior.Synchronous, CancellationToken.None).GetAwaiter().GetResult();
 

src/MySqlConnector/MySqlClient/MySqlDataReader.cs

@@ -108,7 +108,7 @@ private ValueTask<ResultSet> ScanResultSetAsync(IOBehavior ioBehavior, ResultSet
 
 		private async Task<ResultSet> ScanResultSetAsyncAwaited(IOBehavior ioBehavior, ResultSet resultSet, CancellationToken cancellationToken)
 		{
-			using (cancellationToken.Register(Command.Cancel))
+			using (cancellationToken.Register(Command.CancelAction))
 			{
 				try
 				{

src/MySqlConnector/MySqlClient/Results/ResultSet.cs

@@ -162,7 +162,7 @@ private ValueTask<Row> ScanRowAsync(IOBehavior ioBehavior, Row row, Cancellation
 			if (BufferState == ResultSetState.HasMoreData || BufferState == ResultSetState.NoMoreData || BufferState == ResultSetState.None)
 				return new ValueTask<Row>((Row)null);
 
-			using (cancellationToken.Register(Command.Cancel))
+			using (cancellationToken.Register(Command.CancelAction))
 			{
 				var payloadValueTask = Session.ReceiveReplyAsync(ioBehavior, CancellationToken.None);
 				return payloadValueTask.IsCompletedSuccessfully