Custom data extra in call.

[hninaye09]

In low level api, there's option to add custom data to call.

val call = client.call("default", "123")
call.create(memberIds = members, custom = mapOf("color" to "red"), ring = true)

But creating outgoing call with StreamCallActivity.callIntent() doesn't have that option. How to achieve passing extra data from caller to call via call's custom field.