Reassembled unordered message is received broken

[enobufs]

Your environment.

• Version: v1.6.11

What did you do?

I was writing test with sctp stream configured for unordered delivery.

What did you expect?

Sending messages, although the order could be different, each messages are identical to the original messages.

What happened?

Each message is broken when the message is larger than the max segment size, 1200.

I know the cause.

The assumption of the design was wrong. When I introduced pendingQueue which has ordered and unordered queues assuming that chunks in the unordered queue can be completely unordered. But 'unordered' should only apply to user messages. Not at the chunk level.

When a message is large, fragmented into multiple chunks with the current code, the message could be corrupted. (this has been repro'ed in my local test. PR is incoming)