docs(autonomi): add example Rust code

autonomi/README.md

@@ -9,9 +9,47 @@ Connect to and build on the Autonomi network.
 
 Add the autonomi crate to your `Cargo.toml`:
 
-```toml
-[dependencies]
-autonomi = { path = "../autonomi", version = "0.1.0" }
+```sh
+# `cargo add` adds dependencies to your Cargo.toml manifest file
+cargo add autonomi
+```
+
+### Example
+
+```rust
+use autonomi::{Bytes, Client, Wallet};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // Default wallet of testnet.
+    let key = "0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80";
+
+    let client = Client::connect(&["/ip4/127.0.0.1/udp/1234/quic-v1".parse()?]).await?;
+    let wallet = Wallet::new_from_private_key(Default::default(), key)?;
+
+    // Put and fetch data.
+    let data_addr = client
+        .data_put(Bytes::from("Hello, World"), wallet.clone().into())
+        .await?;
+    let _data_fetched = client.data_get(data_addr).await?;
+
+    // Put and fetch directory from local file system.
+    let dir_addr = client.dir_upload("files/to/upload".into(), &wallet).await?;
+    client
+        .dir_download(dir_addr, "files/downloaded".into())
+        .await?;
+
+    Ok(())
+}
+```
+
+In the above example the wallet is setup to use the default EVM network (Arbitrum One). Instead we can use a different network:
+```rust
+use autonomi::{EvmNetwork, Wallet};
+// Arbitrum Sepolia
+let wallet = Wallet::new_from_private_key(EvmNetwork::ArbitrumSepolia, key)?;
+// Custom (e.g. local testnet)
+let wallet = Wallet::new_from_private_key(EvmNetwork::new_custom("<rpc URL>", "<payment token address>", "<data payment address>"), key)?;
 ```
 
 ## Running tests

autonomi/examples/put_and_dir_upload.rs

@@ -0,0 +1,24 @@
+use autonomi::{Bytes, Client, Wallet};
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    // Default wallet of testnet.
+    let key = "0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80";
+
+    let client = Client::connect(&["/ip4/127.0.0.1/udp/1234/quic-v1".parse()?]).await?;
+    let wallet = Wallet::new_from_private_key(Default::default(), key)?;
+
+    // Put and fetch data.
+    let data_addr = client
+        .data_put(Bytes::from("Hello, World"), wallet.clone().into())
+        .await?;
+    let _data_fetched = client.data_get(data_addr).await?;
+
+    // Put and fetch directory from local file system.
+    let dir_addr = client.dir_upload("files/to/upload".into(), &wallet).await?;
+    client
+        .dir_download(dir_addr, "files/downloaded".into())
+        .await?;
+
+    Ok(())
+}