Enhance SkipBox to support skipping on non-FileChannel DataSource

[zhou-hao]

Currently, SkipBox relies on FileChannel-specific behavior to efficiently skip box content.
When the underlying DataSource is not backed by a FileChannel (e.g. streaming sources, in-memory sources, custom DataSource implementations), SkipBox cannot skip data efficiently and may fail or require full reads.

This limitation makes it difficult to use SkipBox in streaming or non-file-based scenarios.

mp4parser/isoparser/src/main/java/org/mp4parser/SkipBox.java

Line 54 in ff13790

throw new RuntimeException("Cannot skip box "+type+" if data source is not seekable");

Would the maintainers be open to adding this fallback mechanism to SkipBox to improve support for non-FileChannel data sources?

 long remaining = contentSize;
  ByteBuffer skipBuffer = ByteBuffer.allocate((int) Math.min(8192, remaining));
  while (remaining > 0) {
      skipBuffer.clear();
      if (remaining < skipBuffer.capacity()) {
          skipBuffer.limit((int) remaining);
      }
      int read = dataSource.read(skipBuffer);
      if (read < 0) {
          throw new EOFException("Unexpected end of stream while skipping mdat box, remaining: " + remaining);
      }
      remaining -= read;
  }