add note about plugin feature in cargo

closes #1

README.md

@@ -109,14 +109,26 @@ fn main() {
 }
 ```
 
-after adding it to your project's dependencies (eg, `cargo add julid-rs`; note the package name is
+after adding it to your project's dependencies (eg, `cargo add julid-rs`; the package name is
 "julid-rs", but the library name as used in your `use` statements is just "julid"). By default, it
 will also include trait implementations for using Julids with
 [SQLx](https://github.com/launchbadge/sqlx), and serializing/deserializing with
 [Serde](https://serde.rs/), via the `sqlx` and `serde` features, respectively. One final default
 optional feature, `chrono`, uses the Chrono crate to return the timestamp as a
-[`DateTime`](https://docs.rs/chrono/latest/chrono/struct.DateTime.html) by adding a `created_at(&self)`
-method to `Julid`.
+[`DateTime`](https://docs.rs/chrono/latest/chrono/struct.DateTime.html) by adding a
+`created_at(&self)` method to `Julid`. See the simple
+[example](https://gitlab.com/nebkor/julid/-/blob/main/examples/benchmark.rs) in the repo.
+
+Something to note: don't enable the `plugin` feature in your Cargo.toml if you're using this crate
+inside your Rust application, *especially* if you're also loading it as an extension in SQLite in
+your application. You'll get a long and confusing runtime panic due to there being multiple
+entrypoints defined with the same name.
+
+## Safety
+There is one `unsafe fn` in this project, `sqlite_julid_init()`, and it is only built for the
+`plugin` feature. The reason for it is that it's interacting with foreign code (SQLite itself) via
+the C interface, which is inherently unsafe. If you are not building the plugin, there is no
+`unsafe` code.
 
 # Thanks