How to pass request body to InvokeHTTP POST Request

[#1]

Hello All,
I am trying to post the POST request (REST API) through Invoke HTTP process, for post request it requires two attributes one as part of HTTP Headers & other as Request Body which is JSON in key value format. Below are the attributes which I am trying to pass:

1)HTTP Header Attribute: This I am defining as Flowfile attribute which are converted as HTTP Headers.
2)Here is the data which has to sent as body of the request,
input_data= {
"request": {
"subject": "aaaaa",
"description": "aaaa",
"requester": {
"id": "1",
"name": "admin"
},
"impact_details": "aaaaa",
"resolution": {
"content": "aaaa"
},
"status": {
"name": "Open"
}
}
}

Approached followed : GenerateFlowFile(property)->ReplaceText->InvokeHTTP
Error (No-Retry):{"response_status":{"status_code":4000,"messages":[{"status_code":4001,"field":"input_data","type":"failed","message":"Value not provided"}],"status":"failed"}}