Kartik: You can't turn off buffering on the Bluetooth module, I'm afraid.
However, we're working on adding a feature to the SDK that can estimate the correct absolute timestamps for the data fairly accurately - probably well enough to try some ERP experiments. Using that, you would then just need to make sure that the other data streams you are synchronizing with Muse are also properly labelled with absolute timestamps.
We might be able to get this up and running quite soon, so please stay tuned and we'll let you know! Thanks for bringing the topic up, we know how important synchronization is to many developers and researchers.
Rxz_14: MuseIO doesn't send EEG data when samples are dropped. It sends out /muse/eeg/dropped_samples messages. Depending on your application, you are probably safe assuming the sampling rate is constant at 220Hz. Kartik's ERP experiments require fairly good time synchronization between a few different data sources, which is when accounting for dropped packets becomes really important.