Async support

Optional async api that can be switched to with the "async" feature flag

.github/workflows/rust.yml

@@ -27,6 +27,8 @@ jobs:
       run: cargo build --examples --all-targets --verbose
     - name: Run tests
       run: cargo test --verbose
+    - name: Run tests (async)
+      run: cargo test --verbose --lib --tests --benches --features async
     - name: Build docs
       run: cargo doc
     - name: Clippy

Cargo.toml

@@ -16,7 +16,9 @@ rust-version = "1.62"
 [dependencies]
 embedded-graphics-core = { version = "0.4", optional = true }
 embedded-hal = "1.0.0"
+embedded-hal-async = { version = "1.0.0", optional = true }
 bit_field = "0.10.1"
+maybe-async = { git = "https://github.com/XLPhere/maybe-async-rs.git", branch = "default_sync", features = ["default_sync"] }
 
 [dev-dependencies]
 embedded-graphics = "0.8"
@@ -47,11 +49,16 @@ required-features = ["linux-dev"]
 name = "epd4in2"
 required-features = ["linux-dev"]
 
+[[example]]
+name = "epd7in5_v2"
+required-features = ["linux-dev"]
+
 [features]
 # Remove the linux-dev feature to build the tests on non  unix systems
 default = ["graphics", "linux-dev", "epd2in13_v3"]
 
 graphics = ["embedded-graphics-core"]
+async = ["embedded-hal-async", "maybe-async/is_async"]
 epd2in13_v2 = []
 epd2in13_v3 = []
 linux-dev = []