Allow to shutdown SchemaDownloader (#6091)

* Allow to shutdown SchemaDownloader

* revert unwanted change

Author: martinbonnin

libraries/apollo-tooling/src/main/kotlin/com/apollographql/apollo/tooling/SchemaDownloader.kt

@@ -189,5 +189,10 @@ object SchemaDownloader {
     return data.graph.variant.latestPublication.schema.document
   }
 
+  fun shutdown() {
+    SchemaHelper.client.dispatcher.executorService.shutdown()
+    SchemaHelper.client.connectionPool.evictAll()
+  }
+  
   inline fun <reified T> Any?.cast() = this as? T
 }

libraries/apollo-tooling/src/main/kotlin/com/apollographql/apollo/tooling/SchemaHelper.kt

@@ -31,10 +31,12 @@ import javax.net.ssl.SSLSocketFactory
 import javax.net.ssl.X509TrustManager
 
 internal object SchemaHelper {
+  internal val client = OkHttpClient()
+
   internal fun newOkHttpClient(insecure: Boolean): OkHttpClient {
     val connectTimeoutSeconds = System.getProperty("okHttp.connectTimeout", "600").toLong()
     val readTimeoutSeconds = System.getProperty("okHttp.readTimeout", "600").toLong()
-    val clientBuilder = OkHttpClient.Builder()
+    val clientBuilder = client.newBuilder()
         .connectTimeout(connectTimeoutSeconds, TimeUnit.SECONDS)
         .readTimeout(readTimeoutSeconds, TimeUnit.SECONDS)