Add documentation for crate features

This closes sfackler#544

Author: bikeshedder

postgres/src/lib.rs

@@ -46,6 +46,20 @@
 //! as an argument. The `NoTls` type in this crate can be used when TLS is not required. Otherwise, the
 //! `postgres-openssl` and `postgres-native-tls` crates provide implementations backed by the `openssl` and `native-tls`
 //! crates, respectively.
+//!
+//! # Features
+//!
+//! The following features can be enabled from `Cargo.toml`:
+//!
+//! | Feature | Description | Extra dependencies | Default |
+//! | ------- | ----------- | ------------------ | ------- |
+//! | `with-bit-vec-0_6` | Enable support for the `bit-vec` crate. | [bit-vec](https://crates.io/crates/bit-vec) 0.6 | no |
+//! | `with-chrono-0_4` | Enable support for the `chrono` crate. | [chrono](https://crates.io/crates/chrono) 0.4 | no |
+//! | `with-eui48-0_4` | Enable support for the `eui48` crate. | [eui48](https://crates.io/crates/eui48) 0.4 | no |
+//! | `with-geo-types-0_4` | Enable support for the `geo-types` crate. | [geo-types](https://crates.io/crates/geo-types) 0.4 | no |
+//! | `with-serde_json-1` | Enable support for the `serde_json` crate. | [eui48](https://crates.io/crates/serde_json) 1.0 | no |
+//! | `with-uuid-0_8` | Enable support for the `uuid` crate. | [uuid](https://crates.io/crates/uuid) 0.8 | no |
+//! | `with-time-0_2` | Enable support for the `time` crate. | [time](https://crates.io/crates/time) 0.2 | no |
 #![doc(html_root_url = "https://docs.rs/postgres/0.17")]
 #![warn(clippy::all, rust_2018_idioms, missing_docs)]
 

tokio-postgres/src/lib.rs

@@ -96,6 +96,21 @@
 //! as an argument. The `NoTls` type in this crate can be used when TLS is not required. Otherwise, the
 //! `postgres-openssl` and `postgres-native-tls` crates provide implementations backed by the `openssl` and `native-tls`
 //! crates, respectively.
+//!
+//! # Features
+//!
+//! The following features can be enabled from `Cargo.toml`:
+//!
+//! | Feature | Description | Extra dependencies | Default |
+//! | ------- | ----------- | ------------------ | ------- |
+//! | `runtime` | Enable convenience API for the connection process based on the `tokio` crate. | [tokio](https://crates.io/crates/tokio) 0.2 with the features `dns`, `net` and `time` | yes |
+//! | `with-bit-vec-0_6` | Enable support for the `bit-vec` crate. | [bit-vec](https://crates.io/crates/bit-vec) 0.6 | no |
+//! | `with-chrono-0_4` | Enable support for the `chrono` crate. | [chrono](https://crates.io/crates/chrono) 0.4 | no |
+//! | `with-eui48-0_4` | Enable support for the `eui48` crate. | [eui48](https://crates.io/crates/eui48) 0.4 | no |
+//! | `with-geo-types-0_4` | Enable support for the `geo-types` crate. | [geo-types](https://crates.io/crates/geo-types) 0.4 | no |
+//! | `with-serde_json-1` | Enable support for the `serde_json` crate. | [eui48](https://crates.io/crates/serde_json) 1.0 | no |
+//! | `with-uuid-0_8` | Enable support for the `uuid` crate. | [uuid](https://crates.io/crates/uuid) 0.8 | no |
+//! | `with-time-0_2` | Enable support for the `time` crate. | [time](https://crates.io/crates/time) 0.2 | no |
 #![doc(html_root_url = "https://docs.rs/tokio-postgres/0.5")]
 #![warn(rust_2018_idioms, clippy::all, missing_docs)]