Add withHttp2 and withoutHttp2

build.sbt

@@ -120,6 +120,8 @@ lazy val client = project
       ProblemFilters.exclude[Problem]("org.http4s.netty.client.Http4sChannelPoolMap.*"),
       ProblemFilters.exclude[Problem]("org.http4s.netty.client.NettyClientBuilder.*"),
       ProblemFilters.exclude[Problem]("org.http4s.netty.client.NettyWSClientBuilder.*"),
+      ProblemFilters.exclude[MissingTypesProblem](
+        "org.http4s.netty.client.Http4sChannelPoolMap$Config$"),
       ProblemFilters.exclude[MissingFieldProblem](
         "org.http4s.netty.client.NettyClientBuilder.SSLContextOption"),
       ProblemFilters.exclude[MissingClassProblem]("org.http4s.netty.client.Http4sHandler$"),

client/src/main/scala/org/http4s/netty/client/Http4sChannelPoolMap.scala

@@ -98,7 +98,11 @@ private[client] class Http4sChannelPoolMap[F[_]](
     )
   }
 
-  def run(request: Request[F]): Resource[F, Response[F]] = {
+  def run(request0: Request[F]): Resource[F, Response[F]] = {
+    val request =
+      if (config.http2 && request0.uri.scheme.contains(Uri.Scheme.https))
+        request0.withHttpVersion(HttpVersion.`HTTP/2`)
+      else request0
     val key = Key(RequestKey.fromRequest(request), request.httpVersion)
 
     for {
@@ -235,7 +239,9 @@ private[client] object Http4sChannelPoolMap {
       maxConnections: Int,
       idleTimeout: Duration,
       proxy: Option[Proxy],
-      sslConfig: SSLContextOption)
+      sslConfig: SSLContextOption,
+      http2: Boolean
+  )
 
   private[client] def fromFuture[F[_]: Async, A](future: => Future[A]): F[A] =
     Async[F].async { callback =>

client/src/main/scala/org/http4s/netty/client/NettyClientBuilder.scala

@@ -35,7 +35,8 @@ class NettyClientBuilder[F[_]](
     transport: NettyTransport,
     sslContext: SSLContextOption,
     nettyChannelOptions: NettyChannelOptions,
-    proxy: Option[Proxy]
+    proxy: Option[Proxy],
+    http2: Boolean
 )(implicit F: Async[F]) {
   type Self = NettyClientBuilder[F]
 
@@ -49,7 +50,8 @@ class NettyClientBuilder[F[_]](
       transport: NettyTransport = transport,
       sslContext: SSLContextOption = sslContext,
       nettyChannelOptions: NettyChannelOptions = nettyChannelOptions,
-      proxy: Option[Proxy] = proxy
+      proxy: Option[Proxy] = proxy,
+      http2: Boolean = http2
   ): NettyClientBuilder[F] =
     new NettyClientBuilder[F](
       idleTimeout,
@@ -61,7 +63,8 @@ class NettyClientBuilder[F[_]](
       transport,
       sslContext,
       nettyChannelOptions,
-      proxy
+      proxy,
+      http2
     )
 
   def withNativeTransport: Self = copy(transport = NettyTransport.defaultFor(Os.get))
@@ -96,6 +99,8 @@ class NettyClientBuilder[F[_]](
   def withProxy(proxy: Proxy): Self = copy(proxy = Some(proxy))
   def withProxyFromSystemProperties: Self = copy(proxy = Proxy.fromSystemProperties)
   def withoutProxy: Self = copy(proxy = None)
+  def withHttp2: Self = copy(http2 = true)
+  def withoutHttp2: Self = copy(http2 = false)
 
   private def createBootstrap: Resource[F, Bootstrap] =
     Resource.make(F.delay {
@@ -116,7 +121,8 @@ class NettyClientBuilder[F[_]](
         maxConnectionsPerKey,
         idleTimeout,
         proxy,
-        sslContext
+        sslContext,
+        http2
       )
       Client[F](new Http4sChannelPoolMap[F](bs, config).run)
     }
@@ -134,6 +140,7 @@ object NettyClientBuilder {
       transport = NettyTransport.defaultFor(Os.get),
       sslContext = SSLContextOption.TryDefaultSSLContext,
       nettyChannelOptions = NettyChannelOptions.empty,
-      proxy = Proxy.fromSystemProperties
+      proxy = Proxy.fromSystemProperties,
+      http2 = false
     )
 }

client/src/test/scala/org/http4s/netty/client/EmberHttp2Test.scala

@@ -53,9 +53,8 @@ class EmberHttp2Test extends IOSuite {
   val client: IOFixture[Client[IO]] = resourceFixture(
     NettyClientBuilder[IO].withNioTransport
       .withSSLContext(EmberHttp2Test.sslContextForClient)
-      .resource
-      .map(client =>
-        Client((req: Request[IO]) => client.run(req.withHttpVersion(HttpVersion.`HTTP/2`)))),
+      .withHttp2
+      .resource,
     "client"
   )