Create thread-safe random

src/util.zig

@@ -1,6 +1,24 @@
 const std = @import("std");
 const root = @import("root");
 
+threadlocal var tls_prng: ?std.rand.DefaultPrng = null;
+
+fn initPrng() void {
+    const higher_seed = (@bitCast(u64, std.Thread.getCurrentId()) & 0xffffffff) << 32;
+    const lower_seed = @bitCast(u64, std.time.milliTimestamp()) & 0xffffffff;
+
+    tls_prng = std.rand.DefaultPrng.init(higher_seed | lower_seed);
+}
+
+pub fn getRandom() std.rand.Random {
+    if (tls_prng) |*prng| {
+        return prng.random();
+    }
+
+    initPrng();
+    return tls_prng.?.random();
+}
+
 pub const Uuid = struct {
     data: [16]u8,