used to specify the destination of a transaction
- INTERNAL - The transfer that's destined for your sub-account. e.g. moving funds from Binance.
- EXTERNAL - The transfer that's destined to outside of your workspace. e.g. to an address.
- SUBACCOUNT - The transfer that's destined to another sub-account within your workspace. e.g. moving funds from one branch to another.
- EXCHANGE - The transfer that's destined for a supported exchange. e.g. moving funds to Binance.