feat: add gif ascii art generate

src/main/kotlin/cn/rtast/fancybot/util/GIF.kt

@@ -13,12 +13,14 @@ import java.awt.image.BufferedImage
 import java.io.ByteArrayOutputStream
 
 fun GifDecoder.makeGif(frames: List<BufferedImage>): ByteArray {
-    val byteArrayOutputStream = ByteArrayOutputStream()
+    val estimatedSize = frames.size * 50 * 1024
+    val byteArrayOutputStream = ByteArrayOutputStream(estimatedSize)
     val encoder = AnimatedGifEncoder()
     encoder.start(byteArrayOutputStream)
     encoder.setRepeat(0)
-    for (i in frames.indices) {
-        encoder.setDelay(this.getDelay(this.frameCount - i - 1))
+    val delays = frames.indices.map { this.getDelay(this.frameCount - it - 1) }
+    frames.indices.forEach { i ->
+        encoder.setDelay(delays[i])
         encoder.addFrame(frames[i])
     }
     encoder.finish()