Consider adding `IBufferWriter<byte>` overloads to `JsonSerializer`

[eiriktsarpalis]

Would exposing JsonSerializer.Serialize accepting IBufferWriter<byte> overloads help in this case?

Originally posted by @eiriktsarpalis in dotnet/aspnetcore#60616 (comment)

[huoyaoyuan]

Is it covered by #68586?

[huoyaoyuan]

Well, the approved (implemented) was changed from IBufferWriter<byte> to PipeWriter.

[eiriktsarpalis]

PipeWriter is necessary for driving the SerializerAsync since it has flushing capability. IBufferWriter<T> does not so we would only be able to use it for the non-async methods.