Add a coroutine friendly API

[GuillaumeTaffin]

Motivations

• Many framework leverage coroutines
• The SSE mechanism that keeps a connection open to send N data also leads very naturally to use coroutines, but the current api forces to add 'runBlocking'-like closures

Would be great to add an alternative suspended API, without adding the coroutine dependency to the project as people will want to opt in this capacity