Refine Redis Command API

Motivation:

It was noticed that many of the commands are cumbersome to use with boilerplate type casting for each use that can be simplified within the library
by doing type conversion before returning the value to an end user.

Modifications:

Many APIs that return a `RESPValue` now have overloads to provide a `RESPValueConvertible` type that the value will be turned into before being returned.

For a few APIs that returned `RESPValue`, they did so as an Optional. Those APIs have been changed to always provide a `RESPValue` and return `.null` in cases where `nil` was returned.

In addition, the `@inlinable` attribute has been removed from any non-generic command API.

Result:

Developers should have less code boilerplate for turning values from `RESPValue` to their desired type with many commands.

Author: Mordil

Sources/RediStack/Commands/BasicCommands.swift

@@ -20,7 +20,6 @@ extension RedisClient {
     /// See [https://redis.io/commands/echo](https://redis.io/commands/echo)
     /// - Parameter message: The message to echo.
     /// - Returns: The message sent with the command.
-    @inlinable
     public func echo(_ message: String) -> EventLoopFuture<String> {
         let args = [RESPValue(bulk: message)]
         return send(command: "ECHO", with: args)
@@ -32,7 +31,6 @@ extension RedisClient {
     /// See [https://redis.io/commands/ping](https://redis.io/commands/ping)
     /// - Parameter message: The optional message that the server should respond with.
     /// - Returns: The provided message or Redis' default response of `"PONG"`.
-    @inlinable
     public func ping(with message: String? = nil) -> EventLoopFuture<String> {
         let args: [RESPValue] = message != nil
             ? [.init(bulk: message!)] // safe because we did a nil pre-check
@@ -47,7 +45,6 @@ extension RedisClient {
     /// [https://redis.io/commands/select](https://redis.io/commands/select)
     /// - Parameter index: The 0-based index of the database that will receive later commands.
     /// - Returns: An `EventLoopFuture` that resolves when the operation has succeeded, or fails with a `RedisError`.
-    @inlinable
     public func select(database index: Int) -> EventLoopFuture<Void> {
         let args = [RESPValue(bulk: index)]
         return send(command: "SELECT", with: args)
@@ -61,7 +58,6 @@ extension RedisClient {
     ///     - first: The index of the first database.
     ///     - second: The index of the second database.
     /// - Returns: `true` if the swap was successful.
-    @inlinable
     public func swapDatabase(_ first: Int, with second: Int) -> EventLoopFuture<Bool> {
         let args: [RESPValue] = [
             .init(bulk: first),
@@ -77,7 +73,6 @@ extension RedisClient {
     /// [https://redis.io/commands/auth](https://redis.io/commands/auth)
     /// - Parameter password: The password to authenticate with.
     /// - Returns: A `NIO.EventLoopFuture` that resolves if the password was accepted, otherwise it fails.
-    @inlinable
     public func authorize(with password: String) -> EventLoopFuture<Void> {
         let args = [RESPValue(bulk: password)]
         return send(command: "AUTH", with: args)
@@ -89,7 +84,6 @@ extension RedisClient {
     /// [https://redis.io/commands/del](https://redis.io/commands/del)
     /// - Parameter keys: A list of keys to delete from the database.
     /// - Returns: The number of keys deleted from the database.
-    @inlinable
     public func delete(_ keys: [RedisKey]) -> EventLoopFuture<Int> {
         guard keys.count > 0 else { return self.eventLoop.makeSucceededFuture(0) }
 
@@ -103,7 +97,6 @@ extension RedisClient {
     /// [https://redis.io/commands/del](https://redis.io/commands/del)
     /// - Parameter keys: A list of keys to delete from the database.
     /// - Returns: The number of keys deleted from the database.
-    @inlinable
     public func delete(_ keys: RedisKey...) -> EventLoopFuture<Int> {
         return self.delete(keys)
     }
@@ -116,7 +109,6 @@ extension RedisClient {
     ///     - key: The key to set the expiration on.
     ///     - timeout: The time from now the key will expire at.
     /// - Returns: `true` if the expiration was set.
-    @inlinable
     public func expire(_ key: RedisKey, after timeout: TimeAmount) -> EventLoopFuture<Bool> {
         let args: [RESPValue] = [
             .init(bulk: key),
@@ -136,16 +128,15 @@ extension RedisClient {
     /// [https://redis.io/commands/scan](https://redis.io/commands/scan)
     /// - Parameters:
     ///     - position: The cursor position to start from.
-    ///     - count: The number of elements to advance by. Redis default is 10.
     ///     - match: A glob-style pattern to filter values to be selected from the result set.
+    ///     - count: The number of elements to advance by. Redis default is 10.
     /// - Returns: A cursor position for additional invocations with a limited collection of keys found in the database.
-    @inlinable
     public func scan(
         startingFrom position: Int = 0,
-        count: Int? = nil,
-        matching match: String? = nil
+        matching match: String? = nil,
+        count: Int? = nil
     ) -> EventLoopFuture<(Int, [String])> {
-        return _scan(command: "SCAN", nil, position, count, match)
+        return _scan(command: "SCAN", nil, position, match, count)
     }
 
     @usableFromInline
@@ -154,8 +145,8 @@ extension RedisClient {
         resultType: T.Type = T.self,
         _ key: RedisKey?,
         _ pos: Int,
-        _ count: Int?,
-        _ match: String?
+        _ match: String?,
+        _ count: Int?
     ) -> EventLoopFuture<(Int, T)>
         where
         T: RESPValueConvertible