Document present_mode_from_env in iced_wgpu

wgpu/src/settings.rs

@@ -52,6 +52,18 @@ impl From<graphics::Settings> for Settings {
     }
 }
 
+/// Obtains a [`wgpu::PresentMode`] from the current environment
+/// configuration, if set.
+///
+/// The value returned by this function can be changed by setting
+/// the `ICED_PRESENT_MODE` env variable. The possible values are:
+///
+/// - `vsync` → [`wgpu::PresentMode::AutoVsync`]
+/// - `no_vsync` → [`wgpu::PresentMode::AutoNoVsync`]
+/// - `immediate` → [`wgpu::PresentMode::Immediate`]
+/// - `fifo` → [`wgpu::PresentMode::Fifo`]
+/// - `fifo_relaxed` → [`wgpu::PresentMode::FifoRelaxed`]
+/// - `mailbox` → [`wgpu::PresentMode::Mailbox`]
 pub fn present_mode_from_env() -> Option<wgpu::PresentMode> {
     let present_mode = std::env::var("ICED_PRESENT_MODE").ok()?;