Clear the deflater's byte array reference (#1612)

Even though the content of this array isn't read, it looks like
deflater may still interfere by making a pair of calls to
GetPrimitiveArrayCritical + ReleasePrimitiveArrayCritical.

Closes: #1608

Co-authored-by: Jesse Wilson <[email protected]>

Author: swankjesse

okio/src/jvmMain/kotlin/okio/DeflaterSink.kt

@@ -18,6 +18,7 @@
 package okio
 
 import java.util.zip.Deflater
+import okio.internal.EMPTY_BYTE_ARRAY
 
 actual class DeflaterSink internal actual constructor(
   private val sink: BufferedSink,
@@ -51,6 +52,10 @@ actual class DeflaterSink internal actual constructor(
 
       remaining -= toDeflate
     }
+
+    // Deflater still holds a reference to the most recent segment's byte array. That can cause
+    // problems in JNI, so clear it now. https://github.com/square/okio/issues/1608
+    deflater.setInput(EMPTY_BYTE_ARRAY, 0, 0)
   }
 
   private fun deflate(syncFlush: Boolean) {

okio/src/jvmMain/kotlin/okio/internal/-ZlibJvm.kt

@@ -36,3 +36,5 @@ internal actual fun datePartsToEpochMillis(
   calendar.set(year, month - 1, day, hour, minute, second)
   return calendar.time.time
 }
+
+internal val EMPTY_BYTE_ARRAY = byteArrayOf()