class SyncConfiguration {
  companion object {
    fun defaultConfig(user: User, partitionValue: Integer?, schema: Set<RealmObject>)
    fun defaultConfig(user: User, partitionValue: Long?, schema: Set<RealmObject>)
    fun defaultConfig(user: User, partitionValue: String?, schema: Set<RealmObject>)
    fun defaultConfig(user: User, partitionValue: ObjectId?, schema: Set<RealmObject>)
  }

  val user: User
  val partitionValue: Any  val schema: Set<KClass<RealmObject>>

  class Builder {
    constructor(user: User, partitionValue: Integer?, schema: Set<RealmObject>) 
    constructor(user: User, partitionValue: Long?, schema: Set<RealmObject>)
    constructor(user: User, partitionValue: String?, schema: Set<RealmObject>)
    constructor(user: User, partitionValue: ObjectId?, schema: Set<RealmObject>)  
  }
}