Introduce UtcOffset.ZERO constant

Author: ilya-g

core/common/src/UtcOffset.kt

@@ -13,6 +13,7 @@ public expect class UtcOffset {
     public val totalSeconds: Int
 
     public companion object {
+        public val ZERO: UtcOffset
         public fun parse(offsetString: String): UtcOffset
     }
 }

core/common/test/TimeZoneTest.kt

@@ -17,6 +17,7 @@ class TimeZoneTest {
         val utc: FixedOffsetTimeZone = TimeZone.UTC
         println(utc)
         assertEquals("Z", utc.id)
+        assertEquals(UtcOffset.ZERO, utc.offset)
         assertEquals(0, utc.offset.totalSeconds)
         assertEquals(utc.offset, utc.offsetAt(Clock.System.now()))
     }

core/js/src/UtcOffset.kt

@@ -18,6 +18,9 @@ public actual class UtcOffset(internal val zoneOffset: ZoneOffset) {
     override fun toString(): String = zoneOffset.toString()
 
     public actual companion object {
+
+        public actual val ZERO: UtcOffset = UtcOffset(ZoneOffset.UTC)
+
         public actual fun parse(offsetString: String): UtcOffset = try {
             ZoneOffset.of(offsetString).let(::UtcOffset)
         } catch (e: Throwable) {

core/jvm/src/UtcOffsetJvm.kt

@@ -19,6 +19,9 @@ public actual class UtcOffset(internal val zoneOffset: ZoneOffset) {
     override fun toString(): String = zoneOffset.toString()
 
     public actual companion object {
+
+        public actual val ZERO: UtcOffset = UtcOffset(ZoneOffset.UTC)
+
         public actual fun parse(offsetString: String): UtcOffset = try {
             ZoneOffset.of(offsetString).let(::UtcOffset)
         } catch (e: DateTimeException) {

core/native/src/UtcOffset.kt

@@ -20,7 +20,7 @@ public actual class UtcOffset internal constructor(public actual val totalSecond
 
     public actual companion object {
 
-        internal val ZERO: UtcOffset = UtcOffset(0)
+        public actual val ZERO: UtcOffset = UtcOffset(0)
 
         public actual fun parse(offsetString: String): UtcOffset {
             if (offsetString == "Z") {