fix experimental stuff

Author: cijothomas

opentelemetry-appender-tracing/src/layer.rs

@@ -115,6 +115,10 @@ impl<LR: LogRecord> tracing::field::Visit for EventVisitor<'_, LR> {
     }
 
     fn record_u64(&mut self, field: &tracing::field::Field, value: u64) {
+        #[cfg(feature = "experimental_metadata_attributes")]
+        if is_duplicated_metadata(field.name()) {
+            return;
+        }
         match i64::try_from(value) {
             Ok(signed) => {
                 self.log_record
@@ -790,6 +794,10 @@ mod tests {
             TraceFlags::SAMPLED
         );
 
+        for attribute in log.record.attributes_iter() {
+            println!("key: {:?}, value: {:?}", attribute.0, attribute.1);
+        }
+
         // Attributes can be polluted when we don't use this feature.
         #[cfg(feature = "experimental_metadata_attributes")]
         assert_eq!(log.record.attributes_iter().count(), 4);