feat: introduce feature to disable blocking mode

CHANGELOG.md

@@ -650,6 +650,7 @@ Initial release
 
 * [#902] Use `core::ptr::addr_of_mut!` instead of `&mut` on mutable statics. No observable change.
 * [#901] `defmt-rtt`: Update to critical-section 1.2
+* [#915] Introduced `disable-blocking-mode` feature
 
 ### [defmt-rtt-v0.4.1] (2024-05-13)
 

firmware/defmt-rtt/Cargo.toml

@@ -10,6 +10,9 @@ readme = "README.md"
 repository = "https://github.com/knurling-rs/defmt"
 version = "0.4.1"
 
+[features]
+disable-blocking-mode = []
+
 [dependencies]
 defmt = { version = "0.3", path = "../../defmt" }
 critical-section = "1.2"

firmware/defmt-rtt/src/channel.rs

@@ -27,8 +27,8 @@ impl Channel {
         // the host-connection-status is only modified after RAM initialization while the device is
         // halted, so we only need to check it once before the write-loop
         let write = match self.host_is_connected() {
-            true => Self::blocking_write,
-            false => Self::nonblocking_write,
+            true if cfg!(not(feature = "disable-blocking-mode")) => Self::blocking_write,
+            _ => Self::nonblocking_write,
         };
 
         while !bytes.is_empty() {

firmware/defmt-rtt/src/lib.rs

@@ -18,6 +18,9 @@
 //!
 //! `defmt::flush` would also block forever in that case.
 //!
+//! If losing data is not an concern you can disable blocking mode by enabling the feature
+//! `disable-blocking-mode`
+//!
 //! # Critical section implementation
 //!
 //! This crate uses [`critical-section`](https://github.com/rust-embedded/critical-section) to ensure only one thread