What one batch's reply said about the messages inside it.
reasons: string[]
One reason per refused message, redacted for the operator.
refused: number
How many of the batch's messages the provider refused outright.
unconfirmed: number
How many messages the reply did not account for. The provider took the batch, so these may or may not have been sent. They are neither sent nor refused, and either claim would be one we cannot stand behind.