OptionalmaxMaximum payment amount authorized
OptionalminMinimum acceptable settlement amount
OptionalunitBilling unit (e.g., "token", "request", "second")
OptionalunitPrice per unit in smallest denomination
OptionalspenderFacilitator address that will be approved as spender
Extra fields for TRON upto payment requirements.
Included in the PaymentRequirements.extra field to communicate upto-specific parameters to the client.