Logged .NET events with the time they happened (#1042)

app/MindWork AI Studio/Tools/Rust/LogEventRequest.cs

@@ -1,5 +1,14 @@
 namespace AIStudio.Tools.Rust;
 
+/// <summary>
+/// A log event the Rust runtime writes to the log file.
+/// </summary>
+/// <param name="Timestamp">When the event happened, in the round-trip format of TerminalLogger.FormatTransportTimestamp, e.g., 2026-10-09T17:53:54.5629130+00:00. The Rust runtime logs the event with this time; when it cannot read it, the event shows the time it arrived instead.</param>
+/// <param name="Level">The log level.</param>
+/// <param name="Category">The category of the log event.</param>
+/// <param name="Message">The log message.</param>
+/// <param name="Exception">Optional exception message.</param>
+/// <param name="StackTrace">Optional exception stack trace.</param>
 public readonly record struct LogEventRequest(
     string Timestamp,
     string Level,

app/MindWork AI Studio/Tools/Services/RustService.Log.cs

@@ -16,7 +16,7 @@ public sealed partial class RustService
     /// <summary>
     /// Sends a log event to the Rust runtime.
     /// </summary>
-    /// <param name="timestamp">The timestamp of the log event.</param>
+    /// <param name="timestamp">When the log event happened, formatted by TerminalLogger.FormatTransportTimestamp.</param>
     /// <param name="level">The log level.</param>
     /// <param name="category">The category of the log event.</param>
     /// <param name="message">The log message.</param>

app/MindWork AI Studio/Tools/TerminalLogger.cs

@@ -1,4 +1,5 @@
 using System.Collections.Concurrent;
+using System.Globalization;
 
 using AIStudio.Tools.Rust;
 using AIStudio.Tools.Services;
@@ -59,7 +60,9 @@ public sealed class TerminalLogger() : ConsoleFormatter(FORMATTER_NAME)
     public override void Write<TState>(in LogEntry<TState> logEntry, IExternalScopeProvider? scopeProvider, TextWriter textWriter)
     {
         var message = logEntry.Formatter(logEntry.State, logEntry.Exception);
-        var timestamp = DateTimeOffset.UtcNow.ToString("yyyy-MM-dd HH:mm:ss.fff");
+        var now = DateTimeOffset.UtcNow;
+        var timestamp = now.ToString("yyyy-MM-dd HH:mm:ss.fff", CultureInfo.InvariantCulture);
+        var transportTimestamp = FormatTransportTimestamp(now);
         var logLevel = logEntry.LogLevel.ToString();
         var category = logEntry.Category;
         var exceptionMessage = logEntry.Exception?.Message;
@@ -85,13 +88,26 @@ public sealed class TerminalLogger() : ConsoleFormatter(FORMATTER_NAME)
 
         // Send log event to Rust via API (fire-and-forget):
         if (RUST_SERVICE is not null)
-            RUST_SERVICE.LogEvent(timestamp, logLevel, category, message, exceptionMessage, stackTrace);
+            RUST_SERVICE.LogEvent(transportTimestamp, logLevel, category, message, exceptionMessage, stackTrace);
         
         // Buffer early log events until the RustService is available:
         else
-            EARLY_LOG_BUFFER.Enqueue(new LogEventRequest(timestamp, logLevel, category, message, exceptionMessage, stackTrace));
+            EARLY_LOG_BUFFER.Enqueue(new LogEventRequest(transportTimestamp, logLevel, category, message, exceptionMessage, stackTrace));
     }
 
+    /// <summary>
+    /// Formats the time of a log event for the Rust runtime.
+    /// </summary>
+    /// <remarks>
+    /// The round-trip format is ISO 8601 with seven fractional digits and the offset, e.g.,
+    /// 2026-10-09T17:53:54.5629130+00:00, and it is the same in every culture. The Rust runtime
+    /// reads it as RFC 3339, so it can log the event with the time it happened instead of the
+    /// time it arrived.
+    /// </remarks>
+    /// <param name="timestamp">The time of the log event.</param>
+    /// <returns>The time in the round-trip format.</returns>
+    public static string FormatTransportTimestamp(DateTimeOffset timestamp) => timestamp.ToString("O", CultureInfo.InvariantCulture);
+
     private static string GetColorForLogLevel(LogLevel logLevel) => logLevel switch
     {
         LogLevel.Trace => ANSI_GRAY,