Remove TagTransformer and improve TagWriter.

OpenTelemetry.sln

@@ -260,8 +260,6 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Shared", "Shared", "{A49299
 		src\Shared\SemanticConventions.cs = src\Shared\SemanticConventions.cs
 		src\Shared\SpanAttributeConstants.cs = src\Shared\SpanAttributeConstants.cs
 		src\Shared\StatusHelper.cs = src\Shared\StatusHelper.cs
-		src\Shared\TagTransformer.cs = src\Shared\TagTransformer.cs
-		src\Shared\TagTransformerJsonHelper.cs = src\Shared\TagTransformerJsonHelper.cs
 		src\Shared\ThreadSafeRandom.cs = src\Shared\ThreadSafeRandom.cs
 	EndProjectSection
 EndProject

src/OpenTelemetry.Exporter.Console/Implementation/ConsoleTagWriter.cs

@@ -51,10 +51,10 @@ protected override void WriteBooleanTag(ref ConsoleTag consoleTag, string key, b
         consoleTag.Value = value ? "true" : "false";
     }
 
-    protected override void WriteStringTag(ref ConsoleTag consoleTag, string key, string value)
+    protected override void WriteStringTag(ref ConsoleTag consoleTag, string key, ReadOnlySpan<char> value)
     {
         consoleTag.Key = key;
-        consoleTag.Value = value;
+        consoleTag.Value = value.ToString();
     }
 
     protected override void WriteArrayTag(ref ConsoleTag consoleTag, string key, ArraySegment<byte> arrayUtf8JsonBytes)

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/OtlpTagWriter.cs

@@ -45,9 +45,9 @@ protected override void WriteBooleanTag(ref RepeatedField<OtlpCommon.KeyValue> t
         tags.Add(new OtlpCommon.KeyValue { Key = key, Value = ToAnyValue(value) });
     }
 
-    protected override void WriteStringTag(ref RepeatedField<OtlpCommon.KeyValue> tags, string key, string value)
+    protected override void WriteStringTag(ref RepeatedField<OtlpCommon.KeyValue> tags, string key, ReadOnlySpan<char> value)
     {
-        tags.Add(new OtlpCommon.KeyValue { Key = key, Value = ToAnyValue(value) });
+        tags.Add(new OtlpCommon.KeyValue { Key = key, Value = ToAnyValue(value.ToString()) });
     }
 
     protected override void WriteArrayTag(ref RepeatedField<OtlpCommon.KeyValue> tags, string key, ref OtlpCommon.ArrayValue value)
@@ -95,9 +95,9 @@ public override void WriteBooleanValue(ref OtlpCommon.ArrayValue array, bool val
             array.Values.Add(ToAnyValue(value));
         }
 
-        public override void WriteStringValue(ref OtlpCommon.ArrayValue array, string value)
+        public override void WriteStringValue(ref OtlpCommon.ArrayValue array, ReadOnlySpan<char> value)
         {
-            array.Values.Add(ToAnyValue(value));
+            array.Values.Add(ToAnyValue(value.ToString()));
         }
 
         public override void EndWriteArray(ref OtlpCommon.ArrayValue array)

src/OpenTelemetry.Exporter.Zipkin/Implementation/ZipkinTagWriter.cs

@@ -49,7 +49,7 @@ protected override void WriteFloatingPointTag(ref Utf8JsonWriter writer, string
     protected override void WriteBooleanTag(ref Utf8JsonWriter writer, string key, bool value)
         => writer.WriteString(key, value ? "true" : "false");
 
-    protected override void WriteStringTag(ref Utf8JsonWriter writer, string key, string value)
+    protected override void WriteStringTag(ref Utf8JsonWriter writer, string key, ReadOnlySpan<char> value)
         => writer.WriteString(key, value);
 
     protected override void WriteArrayTag(ref Utf8JsonWriter writer, string key, ArraySegment<byte> arrayUtf8JsonBytes)

src/Shared/TagWriter/ArrayTagWriter.cs

@@ -18,7 +18,7 @@ internal abstract class ArrayTagWriter<TArrayState>
 
     public abstract void WriteBooleanValue(ref TArrayState state, bool value);
 
-    public abstract void WriteStringValue(ref TArrayState state, string value);
+    public abstract void WriteStringValue(ref TArrayState state, ReadOnlySpan<char> value);
 
     public abstract void EndWriteArray(ref TArrayState state);
 }

src/Shared/TagWriter/JsonStringArrayTagWriter.cs

@@ -75,7 +75,7 @@ public override void WriteNullValue(ref JsonArrayTagWriterState state)
             state.Writer.WriteNullValue();
         }
 
-        public override void WriteStringValue(ref JsonArrayTagWriterState state, string value)
+        public override void WriteStringValue(ref JsonArrayTagWriterState state, ReadOnlySpan<char> value)
         {
             state.Writer.WriteStringValue(value);
         }