Add weird cargo stuff

Author: rklaehn

Cargo.toml

@@ -83,3 +83,13 @@ name = "fetch-fsm"
 
 [[example]]
 name = "fetch-stream"
+
+# We use this --cfg for documenting the cargo features on which an API
+# is available.  To preview this locally use: RUSTFLAGS="--cfg
+# iroh_docsrs cargo +nightly doc --all-features".  We use our own
+# iroh_docsrs instead of the common docsrs to avoid also enabling this
+# feature in any dependencies, because some indirect dependencies
+# require a feature enabled when using `--cfg docsrs` which we can not
+# do.  To enable for a crate set `#![cfg_attr(iroh_docsrs,
+# feature(doc_cfg))]` in the crate.
+unexpected_cfgs = { level = "warn", check-cfg = ["cfg(iroh_docsrs)"] }