code cleanup + purge anyhow in library code (#157)

input-event/src/error.rs

@@ -0,0 +1,17 @@
+use std::array::TryFromSliceError;
+
+use thiserror::Error;
+
+#[derive(Debug, Error)]
+pub enum ProtocolError {
+    #[error(transparent)]
+    MissingData(#[from] TryFromSliceError),
+    #[error("invalid event id: `{0}`")]
+    InvalidEventId(u8),
+    #[error("invalid pointer event type: `{0}`")]
+    InvalidPointerEventId(u8),
+    #[error("invalid keyboard event type: `{0}`")]
+    InvalidKeyboardEventId(u8),
+    #[error("expected data at idx `{0:?}`")]
+    Data(String),
+}