toMap method
Method-channel payload. null fields are omitted so the native side can
tell "not sent" from "sent", which is what keeps them untouched.
Implementation
Map<String, Object> toMap() => {
'email': ?email,
'name': ?name,
'avatarUrl': ?avatarUrl,
'language': ?language,
'timezone': ?timezone,
'location': ?location,
'plan': ?plan,
'customAttributes': ?customAttributes,
};