How to properly pass custompayload to DialogFlow?

Question

API

just the text is transferred well, and if I also want to transfer the buttons, then nothing works here is an example

$menu = [
    "type"=> "text",
   		"text"=> "This text is being sent via Custom Payload",
   		"keyboard" => [
   			"DefaultHeight"=> true,
   			"Buttons" => [
   				[
     				"Rows" => "2",
     				"Text" => "Написать водителю",
     				"ActionType" => "reply",
     				"Columns" => "2",
     				"ActionBody" => "write_to_driver",
     				"TextSize" => "regular"
   				],
   				[
     				"Rows" => "2",
     				"Text" => "Написать водителю",
     				"ActionType" => "reply",
     				"Columns" => "2",
     				"ActionBody" => "write_to_driver",
     				"TextSize" => "regular"
   				]
   			]
   		]
    
    ];