Add usage example

README.md

@@ -17,11 +17,12 @@ originally created by Brandon Liu for Protomaps.
   - Async `mmap` (Tokio) for local files
   - Async `http` and `https` (Reqwuest + Tokio) for URLs
   - Async `s3` (Rust-S3 + Tokio) for S3-compatible buckets
+- Creating PMTile archives
 
 ## Plans & TODOs
 
 - [ ] Documentation and example code
-- [ ] Support writing and conversion to and from MBTiles + `x/y/z`
+- [ ] Support conversion to and from MBTiles + `x/y/z`
 - [ ] Support additional backends (sync `mmap` and `http` at least)
 - [ ] Support additional async styles (e.g., `async-std`)
 

src/lib.rs

@@ -1,3 +1,19 @@
+//! Read and write `PMTiles` according to the [PMTiles v3 spec](https://github.com/protomaps/PMTiles/blob/master/spec/v3/spec.md).
+//!
+//! ## Writing a `PMTiles` file
+//!
+//! ```rust
+//! use pmtiles::{PmTilesWriter, TileType};
+//! use std::fs::File;
+//!
+//! # let tile_0_0_0 = vec![];
+//! let file = File::create("tiles.pmtiles").unwrap();
+//! let mut writer = PmTilesWriter::new(TileType::Mvt).create(file).unwrap();
+//! writer.add_tile(0, &tile_0_0_0).unwrap();
+//! writer.finish().unwrap();
+//! ```
+//!
+
 #![forbid(unsafe_code)]
 
 #[cfg(feature = "__async")]