use ByteString.toArrayUnsafe where it is safe to do so and improves performance (apache#424)

Author: pjfanning

http-core/src/main/scala/org/apache/pekko/http/impl/engine/http2/hpack/ByteStringInputStream.scala

@@ -28,7 +28,7 @@ private[http2] object ByteStringInputStream {
     bs match {
       case cs: ByteString1C =>
         // TODO optimise, ByteString needs to expose InputStream (esp if array backed, nice!)
-        new ByteArrayInputStream(cs.toArray)
+        new ByteArrayInputStream(cs.toArrayUnsafe())
       case _ =>
         // NOTE: We actually measured recently, and compact + use array was pretty good usually
         apply(bs.compact)

http/src/main/scala/org/apache/pekko/http/scaladsl/coding/DeflateCompressor.scala

@@ -51,7 +51,7 @@ class DeflateCompressor private[coding] (compressionLevel: Int) extends Compress
 
   protected def compressWithBuffer(input: ByteString, buffer: Array[Byte]): ByteString = {
     require(deflater.needsInput())
-    deflater.setInput(input.toArray)
+    deflater.setInput(input.toArrayUnsafe())
     drainDeflater(deflater, buffer)
   }
   protected def flushWithBuffer(buffer: Array[Byte]): ByteString = {

http/src/main/scala/org/apache/pekko/http/scaladsl/coding/GzipCompressor.scala

@@ -41,7 +41,7 @@ private[coding] class GzipCompressor(compressionLevel: Int) extends DeflateCompr
     header() ++ super.finishWithBuffer(buffer) ++ trailer()
 
   private def updateCrc(input: ByteString): Unit = {
-    checkSum.update(input.toArray)
+    checkSum.update(input.toArrayUnsafe())
     bytesRead += input.length
   }
   private def header(): ByteString =
@@ -117,7 +117,7 @@ private[coding] class GzipDecompressor(
   }
   private def crc16(data: ByteString) = {
     val crc = new CRC32
-    crc.update(data.toArray)
+    crc.update(data.toArrayUnsafe())
     crc.getValue.toInt & 0xFFFF
   }
 }

http2-tests/src/test/scala/org/apache/pekko/http/impl/engine/http2/Http2FrameHpackSupport.scala

@@ -58,7 +58,7 @@ trait Http2FrameHpackSupport extends Http2FrameProbeDelegator with Http2FrameSen
   val decoder = new Decoder(Http2Protocol.InitialMaxHeaderListSize, Http2Protocol.InitialMaxHeaderTableSize)
 
   def decodeHeaders(bytes: ByteString): Seq[(String, String)] = {
-    val bis = new ByteArrayInputStream(bytes.toArray)
+    val bis = new ByteArrayInputStream(bytes.toArrayUnsafe())
     val hs = new VectorBuilder[(String, String)]()
 
     decoder.decode(bis,