allow converting Box<dyn RRData> to Box<dyn Any> for owned downcast

lib/dnsbox-base/src/records/unknown.rs

@@ -117,4 +117,8 @@ impl RRData for UnknownRecord {
 	fn as_any(&self) -> &dyn ::std::any::Any {
 		self as _
 	}
+
+	fn as_box_any(self: Box<Self>) -> Box<dyn ::std::any::Any> {
+		self as _
+	}
 }

lib/dnsbox-base/src/ser/rrdata.rs

@@ -108,6 +108,8 @@ pub trait RRData: RRDataPacket + RRDataText + fmt::Debug + 'static {
 
 	fn as_any(&self) -> &dyn Any;
 
+	fn as_box_any(self: Box<Self>) -> Box<dyn Any>;
+
 	// (type, rrdata)
 	fn text(&self) -> Result<(String, String)> {
 		let mut buf = String::new();

lib/dnsbox-derive/src/rrdata.rs

@@ -66,6 +66,10 @@ pub fn rrdata_derive(s: synstructure::Structure) -> proc_macro2::TokenStream {
 			fn as_any(&self) -> &::std::any::Any {
 				self as _
 			}
+
+			fn as_box_any(self: Box<Self>) -> Box<dyn ::std::any::Any> {
+				self as _
+			}
 		},
 	);