IO: fix ByteWritePacket.writePacket size update

Author: Sergey Mashkov

core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/packet/ByteWritePacketImpl.kt

@@ -88,10 +88,12 @@ internal class ByteWritePacketImpl(private val pool: ObjectPool<ByteBuffer>) : B
             is ByteReadPacketEmpty -> {}
             is ByteReadPacketSingle -> {
                 if (p.remaining > 0) {
+                    size += p.remaining
                     last(p.steal().also { it.compact() })
                 }
             }
             is ByteReadPacketImpl -> {
+                size += p.remaining
                 while (p.remaining > 0) {
                     last(p.steal().also { it.compact() })
                 }

core/kotlinx-coroutines-io/src/test/kotlin/kotlinx/coroutines/experimental/io/BytePacketReaderWriterTest.kt

@@ -314,7 +314,9 @@ class BytePacketReaderWriterTest {
 
         val outer = buildPacket {
             append("123")
+            assertEquals(3, size)
             writePacket(inner)
+            assertEquals(6, size)
             append(".")
         }
 
@@ -330,7 +332,9 @@ class BytePacketReaderWriterTest {
 
         val outer = buildPacket {
             append("123")
+            assertEquals(3, size)
             writePacket(inner)
+            assertEquals(100003, size)
             append(".")
         }
 
@@ -346,7 +350,9 @@ class BytePacketReaderWriterTest {
 
         val outer = buildPacket {
             append("123")
+            assertEquals(3, size)
             writePacketUnconsumed(inner)
+            assertEquals(6, size)
             append(".")
         }
 
@@ -362,7 +368,9 @@ class BytePacketReaderWriterTest {
 
         val outer = buildPacket {
             append("123")
+            assertEquals(3, size)
             writePacketUnconsumed(inner)
+            assertEquals(100003, size)
             append(".")
         }