The MinSendBackupAfterMs is now set to 1 ms. Unfortunately this causes backup requests to be send when there is low load. It would be useful if we could set the minimum a little bit higher for certain endpoints.

JSON is the dominant exchange format for REST API.
However, Armeria's WebClient does not provide any JSON-specific APIs.
I believe it should be useful additions if we provide:

WebClient client = WebClient.of();
// Send a serialized JSON object with "applicaiton/json"
HttpResponse response = client.postJson("/items", new MyItem()); 
HttpResponse response = client.putJson("/items"

Describe the proposal

When a SparkConf is invalid for launching our engines, it is better to fail fast instead of waiting for Spark to check while engine bootstrapping.

Motivation

1. Save time to create an invalid

Unused imports are included in the headers of generated files causing 2.12 builds with the default -Yfatal-warnings` setting to fail (unless the correct linting options are unset)

Expected behavior

Scrooge generates files with headers including only the imports the current file needs.

Actual behavior

Scrooge generates import statements for classes that are never used.

St