Suggestion: Consider using StringBuilder pooling

https://github.com/elastic/ecs-dotnet/blob/8bceb425bc616d6d63e7f572ddb56f3c012e774b/src/Elastic.Extensions.Logging.Common/LogEventBuilderExtensions.cs#L148

Consider pooling StringBuilder instances (e.g., via ObjectPool) instead of creating a new one per call; re-use removes per-call allocations and virtually eliminates Gen-0 GC pressure.

Start at src/Elastic.Extensions.Logging.Common/LogEventBuilderExtensions.cs:148 and inspect how the StringBuilder is created and consumed. Check the surrounding logging code for an existing pooling pattern, then verify that pooling removes the per-call allocation without changing the generated log output.

Written by the indexing model from the issue text.