safe to create ByteString from array with no-copy (#821)

* safe to create ByteString from array with no-copy

* another place where we know that the array is private in scope

Author: pjfanning

http-core/src/main/scala/org/apache/pekko/http/impl/engine/ws/FrameEventRenderer.scala

@@ -129,6 +129,6 @@ private[http] final class FrameEventRenderer extends GraphStage[FlowShape[FrameE
       data(maskOffset + 3) = ((mask & 0x000000FF) >> 0).toByte
     }
 
-    ByteString(data)
+    ByteString.fromArrayUnsafe(data)
   }
 }

http/src/main/scala/org/apache/pekko/http/scaladsl/marshalling/PredefinedToEntityMarshallers.scala

@@ -47,7 +47,7 @@ trait PredefinedToEntityMarshallers extends MultipartMarshallers {
       val byteBuffer = contentType.charset.nioCharset.encode(charBuffer)
       val array = new Array[Byte](byteBuffer.remaining())
       byteBuffer.get(array)
-      HttpEntity(contentType, array)
+      HttpEntity(contentType, ByteString.fromArrayUnsafe(array))
     } else HttpEntity.Empty
 
   implicit val DoneMarshaller: ToEntityMarshaller[pekko.Done] =