curl --request POST \
  --url https://api.prime.coinbase.com/v1/portfolios/{portfolio_id}/wallets/{wallet_id}/staking/unstake/preview \
  --header 'Content-Type: application/json' \
  --data '
{
  "amount": "<string>"
}
'

{
  "estimated_amount": "<string>",
  "wallet_id": "<string>",
  "wallet_address": "<string>",
  "current_timestamp": "<string>",
  "validators": [
    {
      "validator_address": "<string>",
      "estimated_unstaking_amount": "<string>",
      "unstake_time_estimate_in_hours": 123,
      "estimated_unstake_date": "<string>"
    }
  ]
}