e018: `Borrow`, `AsRef`, `Deref`: my head hurts now

Three traits which are essential for designing good, Rustic APIs. Notes Borrow, AsRef, and Deref are a little complicated, but they're well-worth understanding. Together, they give you tools for dealing with everything from HashMap and friends to conversions involving smart pointer types to easily using String and str or Vec and slice together. Sponsors * Aleksey Pirogov * Andreas Fischer * Ben Whitley * Cameron Mochrie * Chris Palmer * Christopher Giffard * Daniel Collin * Derek Morr * Jakub "Limeth" Hlusička * Jordan Henderson * Jupp Müller * Keith Gray * Lachlan Collins * Luca Schmid * Matt Rudder * Matthew Piziak * Micael Bergeron * Ovidiu Curcan * Pascal Hertleif * Peter Tillemans * Philipp Keller * Ralph Giles ("rillian") * Raph Levien * reddraggone9 * Ryan Ollos * Steven Murawski * Vesa Kaihlavirta * Vlad Bezden * William Roe * Zaki (Thanks to the couple people donating who opted out of the reward tier, as well. You know who you are!) Become a sponsor * Patreon * Venmo * Dwolla * Cash.me * Flattr * PayPal.me Contact * New Rustacean: * Twitter: @newrustacean * Email: [email protected] * Chris Krycho * GitHub: chriskrycho * Twitter: @chriskrycho