Clarify configuration

README.md

@@ -36,3 +36,12 @@ For more examples, see
 [the src/tests directory](https://github.com/PlasmaPower/brute-force/tree/master/src/tests).
 For documentation on the config or adaptors, see
 [the docs](https://docs.rs/brute-force).
+
+## Configuration
+
+You can change the number of threads used with the environment variable
+`BRUTE_FORCE_THREADS`.
+
+Inside the program, via the Config struct, you can manually override the thread
+count or change how often this library checks if a thread should stop. You can
+also set a timeout via the `brute_force_with_timeout` function.

src/lib.rs

@@ -22,8 +22,8 @@ pub use traits::{Advance, Start};
 #[derive(PartialEq, Eq, Debug, Clone, Copy)]
 pub struct Config {
     /// Number of threads to use.
-    /// Falls back on `BRUTE_FORCE_THREADS`, or if that doesn't exist, the
-    /// number of logical CPU cores.
+    /// Falls back on the `BRUTE_FORCE_THREADS` environment variable, or if
+    /// that doesn't exist, the number of logical CPU cores.
     pub threads: Option<usize>,
     /// The number of iterations to perform between checking if the computation
     /// is done (or timed out). Defaults to 512.