Revert "make Baggage Sendable (#17)" (#23)

This reverts commit 2344023.

.gitignore

@@ -5,5 +5,3 @@ Package.resolved
 /*.xcodeproj
 xcuserdata/
 .swiftpm
-.vscode/
-.history

Sources/InstrumentationBaggage/Baggage.swift

@@ -13,12 +13,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if swift(>=5.5) && canImport(_Concurrency)
-public typealias _Baggage_Sendable = Swift.Sendable
-#else
-public typealias _Baggage_Sendable = Any
-#endif
-
 /// A `Baggage` is a heterogeneous storage type with value semantics for keyed values in a type-safe fashion.
 ///
 /// Its values are uniquely identified via `BaggageKey`s (by type identity). These keys also dictate the type of
@@ -71,8 +65,8 @@ public typealias _Baggage_Sendable = Any
 /// `Baggage` does not expose more functions on purpose to prevent abuse and treating it as too much of an
 /// arbitrary value smuggling container, but only make it convenient for tracing and instrumentation systems which need
 /// to access either specific or all items carried inside a baggage.
-public struct Baggage: _Baggage_Sendable {
-    private var _storage = [AnyBaggageKey: _Baggage_Sendable]()
+public struct Baggage {
+    private var _storage = [AnyBaggageKey: Any]()
 
     /// Internal on purpose, please use `Baggage.TODO` or `Baggage.topLevel` to create an "empty" baggage,
     /// which carries more meaning to other developers why an empty baggage was used.
@@ -157,7 +151,7 @@ extension Baggage {
 
 /// Carried automatically by a "to do" baggage.
 /// It can be used to track where a baggage originated and which "to do" baggage must be fixed into a real one to avoid this.
-public struct TODOLocation: _Baggage_Sendable {
+public struct TODOLocation {
     /// Source file location where the to-do `Baggage` was created
     public let file: String
     /// Source line location where the to-do `Baggage` was created

Sources/InstrumentationBaggage/BaggageKey.swift

@@ -39,9 +39,9 @@
 ///     }
 ///
 /// This pattern allows library authors fine-grained control over which values may be set, and which only get by end-users.
-public protocol BaggageKey: _Baggage_Sendable {
+public protocol BaggageKey {
     /// The type of value uniquely identified by this key.
-    associatedtype Value: _Baggage_Sendable
+    associatedtype Value
 
     /// The human-readable name of this key.
     /// This name will be used instead of the type name when a value is printed.
@@ -62,7 +62,7 @@ extension BaggageKey {
 }
 
 /// A type-erased `BaggageKey` used when iterating through the `Baggage` using its `forEach` method.
-public struct AnyBaggageKey: _Baggage_Sendable {
+public struct AnyBaggageKey {
     /// The key's type represented erased to an `Any.Type`.
     public let keyType: Any.Type