mbostock/d3 — pull request #783 by jasondavies (2012-08-21 14:52:35+00:00)
Title: d3.dsv: make it easier to support streams.

If the current row is terminated with EOL, then we include the current byte position as the third argument to the optional callback.

This allows streaming data to be easily parsed, as the next chunk can be computed using the last non-null
byte position as an offset. In other words, null indicates that the current row may be incomplete.