==

        # Proc.==

(from ruby core)
---
    prc == other -> true or false
    prc.eql?(other) -> true or false

---

Two procs are the same if, and only if, they were created from the same
code block.

    def return_block(&block)
      block
    end

    def pass_block_twice(&block)
      [return_block(&block), return_block(&block)]
    end

    block1, block2 = pass_block_twice { puts 'test' }
    # Blocks might be instantiated into Proc's lazily, so they may, or may not,
    # be the same object.
    # But they are produced from the same code block, so they are equal
    block1 == block2
    #=> true

    # Another Proc will never be equal, even if the code is the "same"
    block1 == proc { puts 'test' }
    #=> false