class Net::SCP

block is given, the SCP session is returned.
SSH session is closed automatically when the block terminates. If no
top of it. If a block is given, the SCP session is yielded, and the
Starts up a new SSH connection and instantiates a new SCP session on

def self.start(host, username, options={})
  session = Net::SSH.start(host, username, options)
  scp = new(session)
  if block_given?
    begin
      yield scp
      session.loop
    ensure
      session.close
    end
  else
    return scp
  end
end