Should RTCDataChannel be able to send blobs/array buffers of size larger than the SCTP buffer?

[youennf]

As discussed in w3c/webrtc-pc#3097, this is not possible in current webrtc implementations but might be a worthwhile addition.

[youennf]

As mentioned in the related issue, there are some things we might want to discuss:

• Is it worthwhile enough?
• Should large blobs be handled differently from large array buffers?
• Should large data sending be tied to the i-data extension?