optimization and docs of executes

src/commonMain/kotlin/com/insanusmokrassar/krontab/Executes.kt

@@ -1,32 +1,53 @@
 package com.insanusmokrassar.krontab
 
 import com.soywiz.klock.DateTime
+import kotlinx.coroutines.Deferred
 import kotlinx.coroutines.delay
 
-suspend inline fun KronScheduler.doWhile(noinline block: suspend () -> Boolean) {
-    do {
-        delay((next() - DateTime.now()).millisecondsLong)
-    } while (block())
+/**
+ * Execute [block] once at the [KronScheduler.next] time and return result of [block] calculation.
+ *
+ * WARNING!!! If you want to launch it in parallel, you must do this explicit.
+ */
+suspend inline fun <T> KronScheduler.doOnce(noinline block: suspend () -> T): T {
+    delay((next() - DateTime.now()).millisecondsLong)
+    return block()
 }
+
+/**
+ * Will [createSimpleScheduler] using [scheduleConfig] and call [doOnce] on it
+ */
+suspend inline fun <T> doOnce(
+    scheduleConfig: String,
+    noinline block: suspend () -> T
+) = createSimpleScheduler(scheduleConfig).doOnce(block)
+
+/**
+ * Will execute [block] while it will return true as a result of its calculation
+ */
+suspend inline fun KronScheduler.doWhile(noinline block: suspend () -> Boolean) {
+    do { val doNext = doOnce(block) } while (doNext)
+}
+
+/**
+ * Will [createSimpleScheduler] using [scheduleConfig] and call [doWhile] with [block]
+ */
 suspend inline fun doWhile(
     scheduleConfig: String,
     noinline block: suspend () -> Boolean
 ) = createSimpleScheduler(scheduleConfig).doWhile(block)
 
+/**
+ * Will execute [block] without any checking of result
+ */
 suspend inline fun KronScheduler.doInfinity(noinline block: suspend () -> Unit) = doWhile {
     block()
     true
 }
+/**
+ * Will [createSimpleScheduler] using [scheduleConfig] and call [doInfinity] with [block]
+ */
 suspend inline fun doInfinity(
     scheduleConfig: String,
     noinline block: suspend () -> Unit
 ) = createSimpleScheduler(scheduleConfig).doInfinity(block)
-
-suspend inline fun KronScheduler.doOnce(noinline block: suspend () -> Unit) = doWhile {
-    block()
-    false
-}
-suspend inline fun doOnce(
-    scheduleConfig: String,
-    noinline block: suspend () -> Unit
-) = createSimpleScheduler(scheduleConfig).doOnce(block)