post https://integration-api.getfront.com/api/v1/transfers/managed/preview
Validate and preview the transfer.
Validates the transfer, calculates the relevant amount in crypto if requested amount was in fiat and updates
the current network fee values.
This endpoint uses the NetworkId field to specify which network will be used to perform the transfer. The target NetworkId
should be selected after configuring the transfer using /configure endpoint.
Returns the PreviewId value that can be used to commit the transfer.