Implement Streaming IO

[nevi-me]

In the case where one wants to just read data from a datasource, and write to another; a streaming version of readers and writers would increase performance by reducing the RAM usage.

One case is where I read data from PostgreSQL and save it to CSV or another supported data source. It would be a plus if I can also be able to throw in some transformations to the process.

I'd also want to do this lazily, with #11 as a foundation