duplicate(chunk:)

Other cases

• case required(chunk: PNG.Chunk, before: PNG.Chunk)

  The decoder encountered a chunk of a type that is not allowed to appear after a previously encountered chunk of a particular type.

• case unexpected(chunk: PNG.Chunk, after: PNG.Chunk)
• case incompleteImageDataCompressedDatastream

  The decoder finished processing the last IDAT chunk before the compressed image data stream was properly terminated.

• case extraneousImageDataCompressedData

  The decoder encountered additional IDAT chunks after the end of the compressed image data stream.

• case extraneousImageData

  The compressed image data stream produces more uncompressed image data than expected.