//! Interact with git credentials in various ways and launch helper programs.//!//! ## Feature Flags#![cfg_attr(    feature = "document-features",    cfg_attr(doc, doc = ::document_features::document_features!()))]#![cfg_attr(docsrs, feature(doc_cfg, doc_auto_cfg))]#![deny(missing_docs, rust_2018_idioms)]#![forbid(unsafe_code)] /// A utility trait to launch a credentials helper, as well as stop them gracefully.pub trait Helper {    /// A way to send data to the helper.    type Send: std::io::Write;    /// A way to receive data from the helper.    type Receive: std::io::Read;     /// Start the helper and provide handles to send and receive from it.    /// If `Action::Get` is provided, it's valid to return `None` for the receive half.    fn start(&mut self, action: &helper::invoke::Action) -> std::io::Result<(Self::Send, Option<Self::Receive>)>;    /// Stop the helper and provide a way to determine it's successful.    fn finish(self) -> std::io::Result<()>;} /// A program/executable implementing the credential helper protocol.#[derive(Debug)]pub enum Program {    /// The kind of program, ready for launch    Ready(program::Kind),    /// The process is running.    Started(std::process::Child),} ///pub mod program; ///pub mod helper; /// Call the `git` credentials helper program performing the given `action`, without any context from git configuration.////// See [`invoke()`][helper::invoke()] for a more flexible implementation.pub fn helper(action: helper::invoke::Action) -> helper::invoke::Result {    helper::invoke(Program::from_kind(program::Kind::Builtin), action)}