fix bug leading to an infinite loop when event name is 'data'
fix bug leading to an infinite loop when event name is 'data'

for streamdataio proxy we chose 'data' as snapshot event name. This leads to an infinite loop in the implemetation as dispatchevent call ondata callback instread of onmessage callback.
streamdataio/EventSource,streamdataio/EventSource,streamdataio/EventSource