Add documentation for etcd (#11)

Added documentation using .docc for etcd.

Co-authored-by: “Ayushi <“[email protected]”>

Author: ayushi2103

Sources/Documentation.docc/Documentation.md

@@ -0,0 +1,93 @@
+# swift-etcd-client-gsoc
+
+A Swift package for interacting with etcd, providing client functionalities such as setting, getting, deleting key-value pairs, and watching keys.
+
+## Overview
+
+This package includes the following key components:
+
+- **EtcdClient:** A client for interacting with an etcd server.
+- **KeyValue:** A struct representing a key-value pair in the etcd server.
+- **RangeRequest:** A struct for fetching a range of key-value pairs from the etcd server.
+- **DeleteRangeRequest:** A struct for deleting a range of key-value pairs from the etcd server.
+- **WatchAsyncSequence:** A struct for handling asynchronous sequences of watch events.
+- **WatchEvent:** A struct representing an event in the etcd watch mechanism.
+
+## Components
+
+### EtcdClient
+
+`EtcdClient` is the primary interface for interacting with the etcd server. It allows you to set, get, delete, and watch key-value pairs.
+
+#### Initialization
+
+```swift
+public init(host: String, port: Int, eventLoopGroup: EventLoopGroup)
+```
+* host The host address of the etcd server.
+* port: The port number of the etcd server.
+* eventLoopGroup: The event loop group to use for this connection.
+
+#### Methods
+* set(_:value:) - Sets a value for a specified key.
+* getRange(_:) - Fetches a range from the etcd server.
+* deleteRange(_:) - Deletes the value for a range from the etcd server.
+* put(_:value:) - Puts a value for a specified key, creating a new key-value pair if it doesn't exist.
+* watch(::): - Watches a specified key for changes.
+
+### KeyValue
+
+`KeyValue` represents a key-value pair in the etcd server.
+
+#### Initialization
+
+```swift
+public init(key: Data, createRevision: Int, modRevision: Int, version: Int, value: Data, lease: Int)
+```
+* key: The key in bytes.
+* createRevision: Revision of the last creation on the key.
+* modRevision: Revision of the last modification on the key.
+* version: The version of the key.
+* value: The value in bytes.
+* lease: The ID of the lease attached to the key.
+
+
+### RangeRequest
+
+`RangeRequest` is used to fetch a range of key-value pairs from the etcd server.
+
+#### Initialization
+
+```swift
+public init(key: Data, rangeEnd: Data? = nil)
+```
+* key: The key to start the range fetch.
+* rangeEnd: The key to end the range fetch.
+
+
+### DeleteRangeRequest
+
+`DeleteRangeRequest` is used to delete a range of key-value pairs from the etcd server.
+
+#### Initialization
+
+```swift
+public init(key: Data, rangeEnd: Data? = nil, prevKV: Bool = false)
+```
+* key: The key of the range to delete.
+* rangeEnd: The key to end the range deletion.
+* prevKV: When set, return the contents of the deleted key-value pairs.
+
+### WatchAsyncSequence
+
+`WatchAsyncSequence` handles asynchronous sequences of watch events from the etcd server.
+
+### WatchEvent
+
+`WatchEvent` represents an event in the etcd watch mechanism.
+
+```swift
+public init(keyValue: KeyValue, previousKeyValue: KeyValue?)
+```
+* keyValue: The current key-value pair associated with the event.
+* previousKeyValue: The previous key-value pair before the event occurred.