Invalid arguments to sendMessage

[dantheman3333]

I'm trying to send a message with

import chrome.runtime.Runtime
Runtime.sendMessage(message = "hi")

This is how it looks in js:

$c_Lchrome_runtime_Runtime$.prototype.sendMessage__sjs_js_UndefOr__sjs_js_Any__sjs_js_UndefOr__sjs_js_UndefOr__V = (function(extensionId, message, options, responseCallback) {
  $g.chrome.runtime.sendMessage(extensionId, message, options, responseCallback)
});

  var x$10 = (void 0);
  $m_Lchrome_runtime_Runtime$();
  var x$11 = (void 0);
  $m_Lchrome_runtime_Runtime$();
  var x$12 = (void 0);
  $m_Lchrome_runtime_Runtime$().sendMessage__sjs_js_UndefOr__sjs_js_Any__sjs_js_UndefOr__sjs_js_UndefOr__V(x$10, "hi", x$11, x$12)

Which seemingly matches chrome.runtime.sendMessage(undefined, "hi", undefined, undefined") but I am getting this error:

Error in event handler for runtime.onMessage: Error: Invalid arguments to sendMessage.
    at $c_Lchrome_runtime_Runtime$.sendMessage__sjs_js_UndefOr__sjs_js_Any__sjs_js_UndefOr__sjs_js_UndefOr__V 

Edit: Running in a content script this does not work:

chrome.runtime.Runtime.sendMessage(extensionId = Runtime.id, message = "hi")

But this does:

chrome.runtime.bindings.Runtime.sendMessage(extensionId = Runtime.id, message = "hi")