Js ingest

Send, request logic is implemented for browser and nodejs. 
In all of the other clients, when a user does StreamWriter.write("11byteslong"), simply 11 bytes get sent in the data field. However, here, 13 bytes are being sent because a string is being preceded and followed by escaped quotes, when it is `stringified`.

To avoid that, don't stringify the data parameter, and expect it as a string, rather than an object. This change also makes it consistent with the StreamWriters in the other languages.