fix: fix IllegalMonitorStateException thrown from BlobAppendableUpload.isOpen() (#3302)

FileChannel.transferTo first checks if the destination is open. Our tests didn't catch this before because they did not probe openness before writing bytes.

Author: BenWhitehead

google-cloud-storage/src/main/java/com/google/cloud/storage/BlobAppendableUploadImpl.java

@@ -111,6 +111,7 @@ public int write(ByteBuffer src) throws IOException {
 
  @Override
  public boolean isOpen() {
+ lock.lock();
  try {
  return buffered.isOpen();
  } finally {

google-cloud-storage/src/test/java/com/google/cloud/storage/ITAppendableUploadTest.java

@@ -15,7 +15,6 @@
  */
 package com.google.cloud.storage;
 
-import static com.google.cloud.storage.ByteSizeConstants._1MiB;
 import static com.google.cloud.storage.TestUtils.assertAll;
 import static com.google.cloud.storage.TestUtils.xxd;
 import static com.google.common.truth.Truth.assertThat;
@@ -44,6 +43,7 @@
 import com.google.cloud.storage.it.runner.registry.Generator;
 import com.google.common.base.MoreObjects;
 import com.google.common.collect.ImmutableList;
+import com.google.common.io.ByteStreams;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.channels.SeekableByteChannel;
@@ -222,7 +222,7 @@ public void testUploadFileUsingAppendable() throws Exception {
  storage.blobAppendableUpload(BlobInfo.newBuilder(bid).build(), p.uploadConfig);
  try (SeekableByteChannel r = tmpFile.reader();
  AppendableUploadWriteableByteChannel w = appendable.open()) {
- long copied = Buffers.copyUsingBuffer(Buffers.allocate(8 * _1MiB), r, w);
+ long copied = ByteStreams.copy(r, w);
  assertThat(copied).isEqualTo(fileSize);
  }
  BlobInfo bi = appendable.getResult().get(5, TimeUnit.SECONDS);