want command to dump heap

[davepacheco]

[yunong]

:+1: This would be a really great way to enable the use of other tools and provide additional functionality.

[davepacheco]

CC @jclulow, who may be interested in this.

For the prototype I created, the file format is described here: https://github.com/joyent/mdb_v8/compare/dev-issue-21#diff-38a6513060f0dadc2b8c2ea5c48a57d9R5229

If there's interest in making this a more useful, interchangeable format, then we should consider this a little more carefully. I like the idea of a plaintext format, but the key-value encoding I used is not particularly good for encoding arbitrary values. We could use JSON. I have a feeling that's rather slow for this, but that's not based on any data.