feat: add experimental RBS support,

TODO:
- add rbs to gemspec
- add rbs tests to gha
- add rbs tests
- consider checking using steep / Steepfile

Steepfile

@@ -0,0 +1,28 @@
+# D = Steep::Diagnostic
+#
+target :lib do
+  signature "sig"
+
+  # check "lib/unleash/client.rbs"                       # Directory name
+  check "lib"                       # Directory name
+  # check "Gemfile"                   # File name
+  # check "app/models/**/*.rb"        # Glob
+  # ignore "lib/templates/*.rb"
+
+  # library "pathname", "set"       # Standard libraries
+  # library "strong_json"           # Gems
+
+  # configure_code_diagnostics(D::Ruby.strict)       # `strict` diagnostics setting
+  # configure_code_diagnostics(D::Ruby.lenient)      # `lenient` diagnostics setting
+  # configure_code_diagnostics do |hash|             # You can setup everything yourself
+  #   hash[D::Ruby::NoMethod] = :information
+  # end
+end
+
+# target :test do
+# #   signature "sig", "sig-private"
+# #
+#   check "spec"
+# #
+# #   # library "pathname", "set"       # Standard libraries
+# end

lib/unleash/client.rbs

@@ -0,0 +1,39 @@
+module Unleash
+  class Client
+    attr_accessor fetcher_scheduled_executor: ScheduledExecutor
+
+    attr_accessor metrics_scheduled_executor: ScheduledExecutor
+
+    def initialize: (*untyped opts) -> void
+
+    def is_enabled?: (untyped feature, ?Context? context, ?bool default_value_param) ?{ () -> bool } -> bool
+
+    # enabled? is a more ruby idiomatic method name than is_enabled?
+    alias enabled? is_enabled?
+
+    # execute a code block (passed as a parameter), if is_enabled? is true.
+    def if_enabled: (untyped feature, ?Context context, ?bool default_value) { (untyped) -> bool } -> (untyped | nil)
+
+    def get_variant: (untyped feature, ?Context context, ?Variant fallback_variant) -> Variant
+
+    # safe shutdown: also flush metrics to server and toggles to disk
+    def shutdown: () -> nil
+
+    # quick shutdown: just kill running threads
+    def shutdown!: () -> nil
+
+    private
+
+    def info: () -> { appName: String, instanceId: String, sdkVersion: String, strategies: Array[String], started: String, interval: Integer }
+
+    def start_toggle_fetcher: () -> nil
+
+    def start_metrics: () -> nil
+
+    def register: () -> nil
+
+    def disabled_variant: () -> Variant
+
+    def first_fetch_is_eager: () -> bool
+  end
+end

lib/unleash/context.rbs

@@ -0,0 +1,21 @@
+module Unleash
+  class Context
+    ATTRS: ::Array[:app_name | :environment | :user_id | :session_id | :remote_address | :current_time]
+
+    def initialize: (?::Hash[String, any] params) -> Context
+
+    def to_s: () -> ::String
+
+    def get_by_name: ((String | Symbol) name) -> any
+
+    def include?: ((String | Symbol) name) -> bool
+
+    private
+
+    # Method to fetch values from hash for two types of keys: string in camelCase and symbol in snake_case
+    def value_for: ((String | Symbol) key, Hash[String, any] params, ?any? default_value) -> any
+
+    # converts CamelCase to snake_case
+    def underscore: ((String | Symbol) camel_cased_word) -> String
+  end
+end

lib/unleash/scheduled_executor.rbs

@@ -0,0 +1,29 @@
+module Unleash
+  class ScheduledExecutor
+    attr_accessor name: String
+
+    attr_accessor interval: Numeric
+
+    attr_accessor max_exceptions: ::Integer
+
+    attr_accessor retry_count: ::Integer
+
+    attr_accessor thread: (Thread | nil)
+
+    attr_accessor immediate_execution: bool
+
+    def initialize: (String name, untyped interval, ?::Integer max_exceptions, ?bool immediate_execution) -> void
+
+    def run: () ?{ () -> nil } -> nil
+
+    def running?: () -> bool
+
+    def exit: () -> nil
+
+    private
+
+    def run_blk: () { () -> nil } -> nil
+
+    def exceeded_max_exceptions?: () -> bool
+  end
+end

lib/unleash/variant.rbs

@@ -0,0 +1,15 @@
+module Unleash
+  class Variant
+    attr_accessor name: String
+
+    attr_accessor enabled: bool
+
+    attr_accessor payload: String
+
+    def initialize: (?::Hash[String, String] params) -> void
+
+    def to_s: () -> ::String
+
+    def ==: (Variant other) -> bool
+  end
+end