Fix unused code warnings on macos

Author: Robo210

src/values/event_values.rs

@@ -5,11 +5,13 @@ use tracing::field;
 use crate::values::*;
 
 // Implemented on the EventBuilder types
+#[allow(dead_code)]
 pub(crate) trait AddFieldAndValue {
     fn add_field_value(&mut self, fv: &crate::values::FieldAndValue);
 }
 
 // We need a wrapper because we cannot implement an external trait (field::Visit) on an external type (EventBuilder)
+#[allow(dead_code)]
 pub(crate) struct EventBuilderVisitorWrapper<T: AddFieldAndValue> {
     wrapped: T,
 }

src/values/mod.rs

@@ -73,6 +73,7 @@ impl From<char> for ValueTypes {
     }
 }
 
+#[allow(dead_code)]
 pub(crate) struct FieldAndValue<'a> {
     #[allow(dead_code)]
     pub(crate) field_name: &'static str,