Add http gzip compression

Previously all the requests were delivered in plan bytes.
This adds ability to send compressed requests to the collector.

README.md

@@ -86,6 +86,7 @@ Alternatively you can write events directly to a S3 bucket:
 "output": {
   "type": "Http"
   "endpoint": "https://my.collector.endpoint.com"
+  "gzip": true
 }
 ```
 

sinks/src/main/scala/com.snowplowanalytics.snowplow.eventgen/Config.scala

@@ -71,7 +71,7 @@ object Config {
     case class File(path: URI) extends Output
     case class PubSub(subscription: String) extends Output
     case class Kafka(brokers: String, topic: String, producerConf: Map[String, String] = Map.empty) extends Output
-    case class Http(endpoint: org.http4s.Uri) extends Output
+    case class Http(endpoint: org.http4s.Uri, gzip: Option[Boolean]) extends Output
   }
 
   val configOpt   = Opts.option[Path]("config", "Path to the configuration HOCON").orNone

sinks/src/main/scala/com.snowplowanalytics.snowplow.eventgen/Http.scala

@@ -22,6 +22,7 @@ import cats.syntax.all._
 
 import cats.effect.Async
 
+import org.http4s.client.middleware.GZip
 import org.http4s.ember.client.EmberClientBuilder
 import org.http4s.Request
 import org.http4s.Header.Raw
@@ -100,7 +101,8 @@ object Http {
       return req
     }
 
-    val httpClient = EmberClientBuilder.default[F].build
+    val emberClient = EmberClientBuilder.default[F].build
+    val httpClient  = if (properties.gzip.getOrElse(false)) emberClient.map(GZip[F](32 * 1024)) else emberClient
 
     st: Stream[F, Main.GenOutput] => {
         Stream