e016: RefCells and code smells

Digging deeper on smart pointers and mutability with `Cell` and `RefCell`. Notes What are the Cell and RefCell types, and when should we use them? Today, we follow up both the detailed discussion of smart pointers in e015 and the closely related discussion in Interview 2 with Raph Levien, and look at two types you need to have a good idea how to deal with if you want to use these smart pointer types more _ergonomically_—that is, how to use them without feeling like you’re beating your head against a wall! Sponsors - Aleksey Pirogov - Chris Palmer - Daniel Collin - Derek Morr - Doug Reeves - Eric Fulmer - Hamza Sheikh - Jakub “Limeth” Hlusička - Keith Gray - Lachlan Collins - Leif Arne Storset - Luca Schmid - Micael Bergeron - Michael Clayton - Pascal Hertleif - Ralph Giles (“rillian”) - Ralph “FriarTech” Loizzo - Raph Levien - reddraggone9 - Ryan Ollos - Vesa Kaihlavirta - William Roe (Thanks to the couple people donating who opted out of the reward tier, as well. You know who you are!) Become a sponsor - Patreon.com/newrustacean - Venmo.com/chriskrycho - Dwolla.com/hub/chriskrycho - Cash.me/$chriskrycho - flattr.com/profile/chriskrycho - PayPal.me/chriskrycho Contact - New Rustacean: - Twitter: @newrustacean - Email: [email protected] - Chris Krycho - GitHub: chriskrycho - Twitter: @chriskrycho