-#[derive(Clone, Debug, PartialEq)]
-pub(super) struct PayerContents(pub Vec<u8>);
+#[derive(Clone, Debug)]
+#[cfg_attr(test, derive(PartialEq))]
+pub(super) struct PayerContents(pub Metadata);
+
+/// TLV record type for [`InvoiceRequest::payer_metadata`] and [`Refund::payer_metadata`].
+///
+/// [`InvoiceRequest::payer_metadata`]: crate::offers::invoice_request::InvoiceRequest::payer_metadata
+/// [`Refund::payer_metadata`]: crate::offers::refund::Refund::payer_metadata
+pub(super) const PAYER_METADATA_TYPE: u64 = 0;