refactor: avoid using magic string

Author: josep-bocanegra

samples/ApiGatewayHttpApiV2Tracing/Voxel.MiddyNet.HttpApiV2TracingSample/ApiGatewayHttpApiV2Tracing.cs

@@ -21,7 +21,7 @@ protected override Task<APIGatewayHttpApiV2ProxyResponse> Handle(APIGatewayHttpA
 
             //If you need to call another system, you need to obtain a traceparent based on the original traceparent
             //received but with the ParentId changed
-            var currentTraceContext = (TraceContext)context.AdditionalContext["TraceContext"];
+            var currentTraceContext = (TraceContext)context.AdditionalContext[TraceContext.TraceContextKey];
             var newTraceContext = TraceContext.MutateParentId(currentTraceContext);
 
             //Now you can use this newTraceContext in your calls 

samples/ApiGatewayTracing/Voxel.MiddyNet.ApiGatewayTracingSample/ApiGatewayTracing.cs

@@ -21,7 +21,7 @@ protected override Task<APIGatewayProxyResponse> Handle(APIGatewayProxyRequest p
 
             //If you need to call another system, you need to obtain a traceparent based on the original traceparent
             //received but with the ParentId changed
-            var currentTraceContext = (TraceContext)context.AdditionalContext["TraceContext"];
+            var currentTraceContext = (TraceContext)context.AdditionalContext[TraceContext.TraceContextKey];
             var newTraceContext = TraceContext.MutateParentId(currentTraceContext);
 
             //Now you can use this newTraceContext in your calls 

src/Voxel.MiddyNet.Tracing.ApiGatewayMiddleware/ApiGatewayHttpApiV2TracingMiddleware.cs

@@ -6,7 +6,6 @@ namespace Voxel.MiddyNet.Tracing.ApiGatewayMiddleware
 {
     public class ApiGatewayHttpApiV2TracingMiddleware : ILambdaMiddleware<APIGatewayHttpApiV2ProxyRequest, APIGatewayHttpApiV2ProxyResponse>
     {
-        private const string TraceContextKey = "TraceContext";
         private const string TraceParentHeaderName = "traceparent";
         private const string TraceStateHeaderName = "tracestate";
         private const string TraceIdHeaderName = "trace-id";
@@ -23,7 +22,7 @@ public Task Before(APIGatewayHttpApiV2ProxyRequest apiGatewayEvent, MiddyNetCont
 
             var traceContext = TraceContext.Handle(traceParentHeaderValue, traceStateHeaderValue);
 
-            context.AdditionalContext.Add(TraceContextKey, traceContext);
+            context.AdditionalContext.Add(TraceContext.TraceContextKey, traceContext);
 
             context.Logger.EnrichWith(new LogProperty(TraceParentHeaderName, traceContext.TraceParent));
             context.Logger.EnrichWith(new LogProperty(TraceStateHeaderName, traceContext.TraceState));

src/Voxel.MiddyNet.Tracing.ApiGatewayMiddleware/ApiGatewayTracingMiddleware.cs

@@ -6,12 +6,10 @@ namespace Voxel.MiddyNet.Tracing.ApiGatewayMiddleware
 {
     public class ApiGatewayTracingMiddleware : ILambdaMiddleware<APIGatewayProxyRequest, APIGatewayProxyResponse>
     {
-        private const string TraceContextKey = "TraceContext";
         private const string TraceParentHeaderName = "traceparent";
         private const string TraceStateHeaderName = "tracestate";
         private const string TraceIdHeaderName = "trace-id";
 
-
         public Task Before(APIGatewayProxyRequest apiGatewayEvent, MiddyNetContext context)
         {
             var traceParentHeaderValue = string.Empty;
@@ -24,7 +22,7 @@ public Task Before(APIGatewayProxyRequest apiGatewayEvent, MiddyNetContext conte
 
             var traceContext = TraceContext.Handle(traceParentHeaderValue, traceStateHeaderValue);
 
-            context.AdditionalContext.Add(TraceContextKey, traceContext);
+            context.AdditionalContext.Add(TraceContext.TraceContextKey, traceContext);
 
             context.Logger.EnrichWith(new LogProperty(TraceParentHeaderName, traceContext.TraceParent));
             context.Logger.EnrichWith(new LogProperty(TraceStateHeaderName, traceContext.TraceState));

src/Voxel.MiddyNet.Tracing.Core/TraceContext.cs

@@ -5,6 +5,8 @@ namespace Voxel.MiddyNet.Tracing.Core
 {
     public class TraceContext
     {
+        public const string TraceContextKey = "TraceContext";
+
         private string version;
         public string TraceId { get; }
         private string parentId;