Document background operations

This patch adds a new section about background operations to the crate
documentation.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index c6c3ff5..9efad91 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -29,6 +29,15 @@
 //! passwords – [`get_hotp_code`][] and [`get_totp_code`][].  Depending on the stick configuration,
 //! these operations are available without authentication or with user authentication.
 //!
+//! # Background operations
+//!
+//! Some commands may start background operations.  During such an operation, every new command
+//! will cause a [`WrongCrc`][] error.  To check whether a background operation is currently
+//! running, use the [`get_operation_status`][] method.
+//!
+//! Background operations are only available on the Nitrokey Storage.  Currently,
+//! [`fill_sd_card`][] is the only command that triggers a background operation.
+//!
 //! # Examples
 //!
 //! Connect to any Nitrokey and print its serial number:
@@ -93,6 +102,8 @@
 //! [`connect_path`]: struct.Manager.html#method.connect_path
 //! [`connect_pro`]: struct.Manager.html#method.connect_pro
 //! [`connect_storage`]: struct.Manager.html#method.connect_storage
+//! [`fill_sd_card`]: struct.Storage.html#method.fill_sd_card
+//! [`get_operation_status`]: struct.Storage.html#method.get_operation_status
 //! [`list_devices`]: fn.list_devices.html
 //! [`manager`]: trait.Device.html#method.manager
 //! [`device`]: struct.User.html#method.device
@@ -101,6 +112,7 @@
 //! [`Admin`]: struct.Admin.html
 //! [`DeviceWrapper`]: enum.DeviceWrapper.html
 //! [`User`]: struct.User.html
+//! [`WrongCrc`]: enum.CommandError.html#variant.WrongCrc
 
 #![warn(missing_docs, rust_2018_compatibility, rust_2018_idioms, unused)]