add debouncedBy extension

coroutines/src/commonTest/kotlin/DebouncedByTests.kt

@@ -0,0 +1,42 @@
+import dev.inmo.micro_utils.coroutines.debouncedBy
+import kotlinx.coroutines.flow.asFlow
+import kotlinx.coroutines.test.runTest
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class DebouncedByTests {
+    @Test
+    fun testThatParallelDebouncingWorksCorrectly() = runTest {
+        val dataToMarkerFactories = listOf(
+            1 to 0,
+            2 to 1,
+            3 to 2,
+            4 to 0,
+            5 to 1,
+            6 to 2,
+            7 to 0,
+            8 to 1,
+            9 to 2,
+        )
+
+        val collected = mutableListOf<Int>()
+
+        dataToMarkerFactories.asFlow().debouncedBy(10L) {
+            it.second
+        }.collect {
+            when (it.second) {
+                0 -> assertEquals(7, it.first)
+                1 -> assertEquals(8, it.first)
+                2 -> assertEquals(9, it.first)
+                else -> error("wtf")
+            }
+            collected.add(it.first)
+        }
+
+        val expectedList = listOf(7, 8, 9)
+        assertEquals(expectedList, collected)
+        assertTrue { collected.containsAll(expectedList) }
+        assertTrue { expectedList.containsAll(collected) }
+    }
+}