SystemTextJsonSerializer.Serialize ignores SerializationFormatting

[VMelnalksnis]

Elastic.Clients.Elasticsearch version: 8.11.0

Elasticsearch version: -

.NET runtime version: 8.0.100

Operating system version: -

Description of the problem including expected versus actual behavior:
Unlike SerializeAsync<T>, Serialize<T> creates a new Utf8JsonWriter, which has its own JsonWriterOptions, which ignore JsonSerializerOptions. If SerializationFormatting.Indented, JsonWriterOptions still defaults to Indented = false.

Steps to reproduce:

1. Call DefaultSourceSerializer.Serialize<T> with SerializationFormatting.Indented
2. See that JSON is in single line

Expected behavior
JSON formatting follows specified SerializationFormatting.

[flobernd]

Thanks for reporting!

Seems like we forgot to pass custom JsonWriterOptions to the Utf8JsonWriter constructor.