Implement asynchronous TAP?

[ivh]

The rate at which the NodeSoftware's XML generator currently procudes output is slightly below 1MB/s (uncompressed). In the example of VALD this means that 5000 transitions, resulting in 10MB of XML, takes 10s to finish.

If we at some point want to run larger requests, it might be worth implementing the asynchronous TAP endpoint at /tap/async. It should be rather straight forward to do.

[misdoro]

In my opinion, async tap may be implemented as a separate universal software package, that would save sync endpoint's output in it's cache and give out when requested