[Tools] Explicitly log new format file creation

src/Tools/dotnet-trace/CommandLine/Commands/CollectCommand.cs

@@ -45,7 +45,7 @@ private static void ConsoleWriteLine(string str)
         /// <param name="buffersize">Sets the size of the in-memory circular buffer in megabytes.</param>
         /// <param name="providers">A list of EventPipe providers to be enabled. This is in the form 'Provider[,Provider]', where Provider is in the form: 'KnownProviderName[:Flags[:Level][:KeyValueArgs]]', and KeyValueArgs is in the form: '[key1=value1][;key2=value2]'</param>
         /// <param name="profile">A named pre-defined set of provider configurations that allows common tracing scenarios to be specified succinctly.</param>
-        /// <param name="format">The desired format of the created trace file.</param>
+        /// <param name="format">If not using the default NetTrace format, an additional file will be emitted with the specified format under the same output name and with the corresponding format extension.</param>
         /// <param name="duration">The duration of trace to be taken. </param>
         /// <param name="clrevents">A list of CLR events to be emitted.</param>
         /// <param name="clreventlevel">The verbosity level of CLR events</param>

src/Tools/dotnet-trace/CommandLine/Options/CommonOptions.cs

@@ -28,7 +28,7 @@ public static Option NameOption() =>
         public static Option FormatOption() =>
             new(
                 alias: "--format",
-                description: $"Sets the output format for the trace file.  Default is {DefaultTraceFileFormat()}.")
+                description: $"If not using the default NetTrace format, an additional file will be emitted with the specified format under the same output name and with the corresponding format extension. The default format is {DefaultTraceFileFormat()}.")
             {
                 Argument = new Argument<TraceFileFormat>(name: "trace-file-format", getDefaultValue: DefaultTraceFileFormat)
             };

src/Tools/dotnet-trace/TraceFileFormatConverter.cs

@@ -36,14 +36,13 @@ internal static string GetConvertedFilename(string fileToConvert, string outputf
 
         internal static void ConvertToFormat(IConsole console, TraceFileFormat format, string fileToConvert, string outputFilename)
         {
-            console.Out.WriteLine($"Writing:\t{outputFilename}");
-
             switch (format)
             {
                 case TraceFileFormat.NetTrace:
                     break;
                 case TraceFileFormat.Speedscope:
                 case TraceFileFormat.Chromium:
+                    console.Out.WriteLine($"Processing trace data file '{fileToConvert}' to create a new {format} file '{outputFilename}'.");
                     try
                     {
                         Convert(console, format, fileToConvert, outputFilename);