I'm using RCC via Websocket API to post Equity Indices data to Refinitiv, using python. 
I'm able to connect to UAT correctly and it seems that the data went through
SENT:
{
  "Ack":true,
  "ID":1,
  "Key":{
    "Name":".FCIWD800USDP",
    "Service":"DDS_TRCE"
  },
  "Message":{
    "Fields":{
      "ASK":2284.0247,
      "DSPLY_NAME":"Hello RCC",
      "PRIMACT_1":106,
      "SEC_ACT_1":26
    },
    "ID":0,
    "Type":"Update"
  },
  "PostID":7,
  "Type":"Post"
}
RECEIVED: 
[
  {
    "AckID":7,
    "ID":1,
    "Type":"Ack"
  }
]
Now to contribute close price / last price what would be the best field to use ?
Having a field list documentation would be helpful
I've looked into the Websocket API Protocol Specification but I can't find it there (https://developers.lseg.com/content/dam/devportal/refinitivrealtimeapi_pdfs/websocket_api_protocol_specification.pdf)
Thanks for your help