Background and Motivation

Both Activity.Tags and Activity.Baggage have a somewhat unusual IEnumerable<KeyValuePair<string, string?>> type, which makes it cumbersome to access individual values (i.e. can't do activity.Tags.TryGetValue(key, out var value)). The latter adds a Activity.GetBaggageItem to compensate, but there isn't an equivalent one for Tags.

Proposed API

namespace System.Diagnostics
{
    public class Activity {
+        public object? GetTagItem(string key)

Usage Examples

Activity activity = ...;

var tag = activity.GetTagItem("Foo");
if (tag != null) {
 // do something with tag 
}

Alternative Designs

The obvious alternative would be to use the dictionary-style bool TryGetTag(string key) instead.

namespace System.Diagnostics
{
    public class Activity {
+        public bool TryGetTag(string key, out string? value)

For consistency, that would likely require changing the existing GetBaggageItem(string key) to bool TryGetBaggage(string key) too, I think.

namespace System.Diagnostics
{
    public class Activity {
-        public string? GetBaggageItem(string key)
+        public bool TryGetBaggage(string key, out object? value)

I think this alternative proposal is much more idiomatic than the existing GetBaggageItem and the proposed GetTagItem.

Risks

None I can think of.