get https://app.bitgo.com/api/v2//tx/fee
Returns the estimated fee for a transaction. UTXO coins will return a fee per kB, while Account-based coins will return a flat fee estimate.
The fee estimate provided by BitGo is higher than the usual network fee. This additional fee is not charged by BitGo but is used to ensure that the transactions are processed faster and do not fail on the blockchain network.