code: function patch(ctx) {
      const statusMethods = Object.assign({}, opts.statusMethods, statusCodeMap)
      ctx.send = respond.bind(ctx, ctx)
  
      // Bind status methods.
      for (const method in statusMethods) {
        const code = statusMethods[method]
        ctx[method] = respond.bind(ctx, ctx, code)
      }
  
      // Bind other methods
      const methods = Object.assign({}, opts.methods)
      for (const method in methods) {
        const fn = methods[method]
        ctx[method] = fn.bind(ctx, ctx)
      }
  
      return ctx
    }
docs: Installs the functions in the context.
  
  @param  {KoaContext} ctx