android使用okhttp可能引发OOM的一个点

public class SignInterceptor implements Interceptor {
  @NonNull
  @Override
  public Response intercept(@NonNull Chain chain) throws IOException {
    Request request = chain.request();
    RequestBody body = request.body();
    byte[] bodyBytes = null;
    if (body != null) {
      final Buffer buffer = new Buffer();
      body.writeTo(buffer);
      bodyBytes = buffer.readByteArray();
    }

    Request.Builder builder = request.newBuilder();
    HttpUrl oldUrl = request.url();
    final String url = oldUrl.toString();
    final String signed = doSignature(url, bodyBytes));
    if (!TextUtils.isEmpty(signed)) {
      builder.addHeader(SIGN_KEY_NAME, signed);
    }
    return chain.proceed(builder.build());
  }
}

 public static RequestBody create(final @Nullable MediaType contentType, final File file) {
  if (file == null) throw new NullPointerException("file == null");

  return new RequestBody() {
   @Override public @Nullable MediaType contentType() {
    return contentType;
   }

   @Override public long contentLength() {
    return file.length();
   }

   @Override public void writeTo(BufferedSink sink) throws IOException {
    try (Source source = Okio.source(file)) {
     sink.writeAll(source);
    }
   }
  };
 }

 public static Source source(File file) throws FileNotFoundException {
  if (file == null) throw new IllegalArgumentException("file == null");
  return source(new FileInputStream(file));
 }
 
 public static Source source(InputStream in) {
  return source(in, new Timeout());
 }

 private static Source source(final InputStream in, final Timeout timeout) {
  return new Source() {
   @Override public long read(Buffer sink, long byteCount) throws IOException {
    try {
     timeout.throwIfReached();
     Segment tail = sink.writableSegment(1);
     int maxToCopy = (int) Math.min(byteCount, Segment.SIZE - tail.limit);
     int bytesRead = in.read(tail.data, tail.limit, maxToCopy);
     if (bytesRead == -1) return -1;
     tail.limit += bytesRead;
     sink.size += bytesRead;
     return bytesRead;
    } catch (AssertionError e) {
     if (isAndroidGetsocknameError(e)) throw new IOException(e);
     throw e;
    }
   }

   @Override public void close() throws IOException {
    in.close();
   }

   @Override public Timeout timeout() {
    return timeout;
   }
  };
 }

 @Override public long writeAll(Source source) throws IOException {
  if (source == null) throw new IllegalArgumentException("source == null");
  long totalBytesRead = 0;
  for (long readCount; (readCount = source.read(this, Segment.SIZE)) != -1; ) {
   totalBytesRead += readCount;
  }
  return totalBytesRead;
 }

 private long writeOrCountBytes(@Nullable BufferedSink sink, boolean countBytes) {
  long byteCount = 0L;

  Buffer buffer;
  if (countBytes) {
   buffer = new Buffer();
  } else {
   buffer = sink.buffer();
  }

  for (int i = 0, size = encodedNames.size(); i  0) buffer.writeByte('&');
   buffer.writeUtf8(encodedNames.get(i));
   buffer.writeByte('=');
   buffer.writeUtf8(encodedValues.get(i));
  }

  if (countBytes) {
   byteCount = buffer.size();
   buffer.clear();
  }

  return byteCount;
 }

 @Override public Buffer write(ByteString byteString) {
  byteString.write(this);
  return this;
 }

  @Override
  public BufferedSink write(@NotNull ByteString byteString) throws IOException {
    byte[] bytes = byteString.toByteArray();
    this.write(bytes);
    return this;
  }

public class FixedSizeSink implements BufferedSink {
  private static final int SEGMENT_SIZE = 4096;
  private final Buffer mBuffer = new Buffer();
  private final int mLimitSize;

  private FixedSizeSink(int size) {
    this.mLimitSize = size;
  }

  @Override
  public Buffer buffer() {
    return mBuffer;
  }

  @Override
  public BufferedSink write(@NotNull ByteString byteString) throws IOException {
    byte[] bytes = byteString.toByteArray();
    this.write(bytes);
    return this;
  }

  @Override
  public BufferedSink write(@NotNull byte[] source) throws IOException {
    this.write(source, 0, source.length);
    return this;
  }

  @Override
  public BufferedSink write(@NotNull byte[] source, int offset,
      int byteCount) throws IOException {
    long available = mLimitSize - mBuffer.size();
    int count = Math.min(byteCount, (int) available);
    android.util.Log.d(TAG, String.format("FixedSizeSink.offset=%d,"
             "count=%d,limit=%d,size=%d",
        offset, byteCount, mLimitSize, mBuffer.size()));
    if (count > 0) {
      mBuffer.write(source, offset, count);
    }
    return this;
  }

  @Override
  public long writeAll(@NotNull Source source) throws IOException {
    this.write(source, mLimitSize);
    return mBuffer.size();
  }

  @Override
  public BufferedSink write(@NotNull Source source, long byteCount) throws IOException {
    final long count = Math.min(byteCount, mLimitSize - mBuffer.size());
    final long BUFFER_SIZE = Math.min(count, SEGMENT_SIZE);
    android.util.Log.d(TAG, String.format("FixedSizeSink.count=%d,limit=%d"
             ",size=%d,segment=%d",
        byteCount, mLimitSize, mBuffer.size(), BUFFER_SIZE));
    long totalBytesRead = 0;
    long readCount;
    while (totalBytesRead