pid header added

Author: Travonka

src/Ydb.Sdk/src/DriverConfig.cs

@@ -1,4 +1,5 @@
-using System.Reflection;
+using System.Diagnostics;
+using System.Reflection;
 using System.Security.Cryptography.X509Certificates;
 using Ydb.Sdk.Auth;
 
@@ -31,6 +32,7 @@ public class DriverConfig
     internal TimeSpan EndpointDiscoveryInterval = TimeSpan.FromMinutes(1);
     internal TimeSpan EndpointDiscoveryTimeout = TimeSpan.FromSeconds(10);
     internal string SdkVersion { get; }
+    private readonly string _pid = Environment.ProcessId.ToString();
 
     public DriverConfig(
         string endpoint,
@@ -61,7 +63,8 @@ public DriverConfig(
     internal Grpc.Core.Metadata GetCallMetadata => new()
     {
         { Metadata.RpcDatabaseHeader, Database },
-        { Metadata.RpcSdkInfoHeader, SdkVersion }
+        { Metadata.RpcSdkInfoHeader, SdkVersion },
+        { Metadata.RpcClientPid , _pid }
     };
 
     private static string FormatEndpoint(string endpoint)

src/Ydb.Sdk/src/Metadata.cs

@@ -2,12 +2,17 @@
 
 internal static class Metadata
 {
+    // Outgoing headers
     public const string RpcDatabaseHeader = "x-ydb-database";
     public const string RpcAuthHeader = "x-ydb-auth-ticket";
     public const string RpcRequestTypeHeader = "x-ydb-request-type";
     public const string RpcTraceIdHeader = "x-ydb-trace-id";
     public const string RpcSdkInfoHeader = "x-ydb-sdk-build-info";
+    public const string RpcClientPid = "x-ydb-client-pid";
+
+    // Incoming headers
     public const string RpcServerHintsHeader = "x-ydb-server-hints";
 
+    //Incoming hints
     public const string GracefulShutdownHint = "session-close";
 }