module Ivar

def self.get_manifest(klass, create: true)

Returns:

(Manifest, nil) - The manifest for the class or module, or nil if not found and create_if_missing is false

Parameters:

create (Boolean) -- Whether to create a new manifest if one doesn't exist
klass (Class, Module) -- The class or module to get a manifest for

def self.get_manifest(klass, create: true)
  return @manifest_registry[klass] if @manifest_registry.key?(klass)
  return nil unless create
  MUTEX.synchronize do
    @manifest_registry[klass] ||= Manifest.new(klass)
  end
end