Rapptz/discord.py ? reverse-engineered prompt

Build me a Python library to make it easy to create Discord bots. I want a modern, feature-rich wrapper that handles the hard parts of the Discord API for me, like rate limiting and managing the connection. The whole thing should be asynchronous using async and await to be fast and efficient.

The library should provide a simple way to listen for events, like when a message is posted, and it should also include a more robust framework for creating commands with a prefix, like >ping. Please make sure to include optional support for voice features, like joining a voice channel. Structure it like a standard installable Python package and include a few clear examples to get a new user started, maybe a simple bot that replies 'pong' when someone messages 'ping'.