Requesting Fingerprinting Wait Time

Hello,

Whenever I do a request, Echonest tells me to wait for some time with the response body looking something like this:

{ status: { version: '4.2', code: 0, message: 'Success' }, track: { status: 'pending', artist: '', title: '', release: '', audio_md5: 'SOME_HASH', bitrate: 192, id: 'SOME_ID_', samplerate: 44100, md5: 'SOME_HASH' } } }

What does it mean when they say pending? And how might I respond to something like this from my server?

Thank you very much!