message: Minor docs for text_cached module
diff: +//! This module is an **experimental** integration of the `gfx_glyph`
  +//! text cache crate. This should offer both much higher performance than
  +//! `ggez::graphics::Text`, and also more features. Use it, enjoy it,
  +//! experiment with it, and offer suggestions for improving the API.
  +//! Hopefully this will be the default method of rendering text for
  +//! ggez 0.5.0.
  +
  use super::*;
  pub use gfx_glyph::{FontId, HorizontalAlign, Scale, VerticalAlign};
  @@ -186,7 +193,6 @@ impl Default for TextCached {
  }
  impl TextCached {
  - // TODO: consider ditching context - it's here for consistency's sake, that's it.
  /// Creates a `TextCached` from a `TextFragment`.
  pub fn new<F>(fragment: F) -> GameResult<TextCached>
  where
  @@ -315,7 +321,9 @@ impl TextCached {
  fn invalidate_cached_metrics(&mut self) {
  if let Ok(mut metrics) = self.cached_metrics.write() {
  *metrics = CachedMetrics::default();
  - return ();
  + // Returning early avoids a double-borrow in the "else"
  + // part.
  + return;
  }
  warn!("Cached metrics RwLock has been poisoned.");
  self.cached_metrics = Arc::new(RwLock::new(CachedMetrics::default()));
  