add work with time zones

src/commonMain/kotlin/dev/inmo/krontab/KronScheduler.kt

@@ -1,6 +1,7 @@
 package dev.inmo.krontab
 
 import com.soywiz.klock.DateTime
+import com.soywiz.klock.DateTimeTz
 import dev.inmo.krontab.internal.toNearDateTime
 
 /**
@@ -19,9 +20,17 @@ interface KronScheduler {
      * @see dev.inmo.krontab.internal.CronDateTimeScheduler.next
      */
     suspend fun next(relatively: DateTime = DateTime.now()): DateTime?
+
+    suspend fun next(relatively: DateTimeTz): DateTimeTz? {
+        return next(relatively.utc) ?.toOffset(relatively.offset)
+    }
 }
 
 suspend fun KronScheduler.nextOrRelative(relatively: DateTime = DateTime.now()): DateTime = next(relatively) ?: getAnyNext(relatively)
+suspend fun KronScheduler.nextOrRelative(relatively: DateTimeTz): DateTimeTz = next(relatively) ?: getAnyNext(relatively)
 suspend fun KronScheduler.nextOrNow(): DateTime = DateTime.now().let {
     next(it) ?: getAnyNext(it)
 }
+suspend fun KronScheduler.nextOrNowWithOffset(): DateTimeTz = DateTimeTz.nowLocal().let {
+    next(it) ?: getAnyNext(it)
+}

src/commonMain/kotlin/dev/inmo/krontab/SchedulerShortcuts.kt

@@ -1,6 +1,7 @@
 package dev.inmo.krontab
 
 import com.soywiz.klock.DateTime
+import com.soywiz.klock.DateTimeTz
 import dev.inmo.krontab.builder.buildSchedule
 import dev.inmo.krontab.internal.*
 import dev.inmo.krontab.internal.CronDateTime
@@ -17,6 +18,7 @@ internal fun getAnyNext(relatively: DateTime) = anyCronDateTime.toNearDateTime(r
 val AnyTimeScheduler: KronScheduler by lazy {
     CronDateTimeScheduler(listOf(anyCronDateTime))
 }
+internal suspend fun getAnyNext(relatively: DateTimeTz) = AnyTimeScheduler.next(relatively)!!
 
 /**
  * [KronScheduler.next] will always return [com.soywiz.klock.DateTime.now] + one second

src/commonTest/kotlin/dev/inmo/krontab/utils/TimeZoneTest.kt

@@ -0,0 +1,23 @@
+package dev.inmo.krontab.utils
+
+import com.soywiz.klock.*
+import dev.inmo.krontab.builder.buildSchedule
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class TimeZoneTest {
+    @Test
+    fun testDifferentTimeZonesReturnsDifferentTimes() {
+        val scheduler = buildSchedule { seconds { every(1) } }
+        val now = DateTime.now()
+        runTest {
+            for (i in 0 .. 24) {
+                val nowTz = now.toOffset(i.hours)
+                val next = scheduler.next(nowTz)!!
+                assertEquals(
+                    (nowTz + 1.seconds).utc.unixMillisLong, next.utc.unixMillisLong
+                )
+            }
+        }
+    }
+}