```ruby
require "benchmark/memory/measurement/metric"

module Benchmark
  module Memory
    # Encapsulate the combined metrics of an action.
    class Measurement
      include Enumerable
      extend Forwardable

      # Create a Measurement from a MemoryProfiler::Results object.
      #
      # @param result [MemoryProfiler::Results] The results of a MemoryProfiler report.
      def self.from_result(result)
        memory  = Metric.new(:memsize, result.total_allocated_memsize, result.total_retained_memsize)
        objects = Metric.new(:objects, result.total_allocated, result.total_retained)
        strings = Metric.new(:strings, result.strings_allocated.size, result.strings_retained.size)

        new(:memory => memory, :objects => objects, :strings => strings)
      end

      # Instantiate a Measurement of memory usage.
      #
      # @param memory [Metric] The memory usage of an action.
      # @param objects [Metric] The object allocations of an action.
      # @param strings [Metric] The string allocations of an action.
      def initialize(memory:, objects:, strings:)
        @metrics = [memory, objects, strings]
      end

      # @return [Array<Metric>] The metrics for the measurement.
      attr_reader :metrics

      # Enumerate through the metrics when enumerating a measurement.
      def_delegator :@metrics, :each
    end
  end
end
```

Add forgotten require of Forwardable
user
```ruby
require "forwardable"
require "benchmark/memory/measurement/metric"

module Benchmark
  module Memory
    # Encapsulate the combined metrics of an action.
    class Measurement
      include Enumerable
      extend Forwardable

      # Create a Measurement from a MemoryProfiler::Results object.
      #
      # @param result [MemoryProfiler::Results] The results of a MemoryProfiler report.
      def self.from_result(result)
        memory  = Metric.new(:memsize, result.total_allocated_memsize, result.total_retained_memsize)
        objects = Metric.new(:objects, result.total_allocated, result.total_retained)
        strings = Metric.new(:strings, result.strings_allocated.size, result.strings_retained.size)

        new(:memory => memory, :objects => objects, :strings => strings)
      end

      # Instantiate a Measurement of memory usage.
      #
      # @param memory [Metric] The memory usage of an action.
      # @param objects [Metric] The object allocations of an action.
      # @param strings [Metric] The string allocations of an action.
      def initialize(memory:, objects:, strings:)
        @metrics = [memory, objects, strings]
      end

      # @return [Array<Metric>] The metrics for the measurement.
      attr_reader :metrics

      # Enumerate through the metrics when enumerating a measurement.
      def_delegator :@metrics, :each
    end
  end
end
```
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