uint256 indexed projectId,
projectIdis the ID of the project that was paid.
payeris the address that paid.
beneficiaryis the address that was specified to receive benefits from the payment, such as the project's tokens.
amountis the amount of tokens that was paid.
beneficiaryTokenCountis the amount of the project's tokens that were issued to the beneficiary as a result of the payment made.
memois a note that was attached.
calleris the address that issued the transaction within which the event was emitted.