general feedback on all the commited stuff (#354)

* mention sdkconfig options needed for spi phy

* remove unwrap

* revert unwrap

examples/eth_spi_async.rs

@@ -1,3 +1,10 @@
+// To be able to use this example, you need to set the following in your sdkconfig.default file:
+// CONFIG_ETH_SPI_ETHERNET_DM9051=y
+// CONFIG_ETH_SPI_ETHERNET_W5500=y
+// CONFIG_ETH_SPI_ETHERNET_KSZ8851SNL=y
+// You only pick one of the three, depending on which chip you have on your board.
+// Also adjust the EspEth::wrap call below to match your board's chip.
+
 fn main() {
     #[cfg(esp32)]
     example::main().unwrap();

examples/eventloop.rs

@@ -12,11 +12,13 @@ use esp_idf_sys::EspError;
 
 use log::info;
 
-fn main() {
+fn main() -> Result<(), EspError> {
     esp_idf_svc::sys::link_patches();
     EspLogger::initialize_default();
 
-    run().unwrap();
+    run()?;
+
+    Ok(())
 }
 
 fn run() -> Result<(), EspError> {