Use parking_lot for wrapping TextureManager

epaint/Cargo.toml

@@ -51,7 +51,7 @@ single_threaded = ["atomic_refcell"]
 
 # Only needed if you plan to use the same fonts from multiple threads.
 # It comes with a minor performance impact.
-multi_threaded = ["parking_lot"]
+multi_threaded = []
 
 
 [dependencies]
@@ -63,7 +63,7 @@ atomic_refcell = { version = "0.1", optional = true }                     # Used
 bytemuck = { version = "1.7.2", optional = true, features = ["derive"] }
 cint = { version = "^0.2.2", optional = true }
 nohash-hasher = "0.2"
-parking_lot = { version = "0.12", optional = true }                       # Using parking_lot over std::sync::Mutex gives 50% speedups in some real-world scenarios.
+parking_lot = "0.12"
 serde = { version = "1", optional = true, features = ["derive", "rc"] }
 
 [dev-dependencies]

epaint/src/texture_handle.rs

@@ -1,8 +1,6 @@
-use crate::{
-    emath::NumExt,
-    mutex::{Arc, RwLock},
-    ImageData, ImageDelta, TextureId, TextureManager,
-};
+use crate::{emath::NumExt, mutex::Arc, ImageData, ImageDelta, TextureId, TextureManager};
+
+use parking_lot::RwLock;
 
 /// Used to paint images.
 ///