"Fix" random crash inside stbi_load_from_memory caused by JVM releasing DirectByteBuffer while it is being used

src/main/kotlin/ru/dbotthepony/kstarbound/defs/image/Image.kt

@@ -315,12 +315,16 @@ class Image private constructor(
 				val getHeight = intArrayOf(0)
 				val components = intArrayOf(0)
 
+				val idata = it.readDirect()
+
 				val data = STBImage.stbi_load_from_memory(
-					it.readDirect(),
+					idata,
 					getWidth, getHeight,
 					components, 0
 				) ?: throw IllegalArgumentException("File $it is not an image or it is corrupted")
 
+				synchronized(idata) {} // memory barrier
+
 				val address = MemoryUtil.memAddress(data)
 				Starbound.CLEANER.register(data) { STBImage.nstbi_image_free(address) }