obfs2 should wait before closing connection on wrong magic/plength
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If the MAGIC_VALUE does not match, or the PADLEN value is greater
than MAX_PADDING, the party receiving it should wait for a random
amount of time then close the connection.
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says the spec.
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if (magic != OBFUSCATE_MAGIC_VALUE)
return -1;
...
says the source.
The spec also doesn't specify the time interval that we should be randomly waiting.