fail to find EAGAIN by experiment

eagain.c

@@ -0,0 +1,27 @@
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+char path[] = "eagain.sock";
+char spam[0xffff0];
+
+int main() {
+    int sock = socket(AF_UNIX, SOCK_STREAM, 0);
+    fcntl(sock, F_SETFL, O_NONBLOCK);
+    struct sockaddr_un addr;
+    addr.sun_family = AF_UNIX;
+    int i = 0;
+    while (1) {
+        addr.sun_path[i] = path[i];
+        if (path[i] == 0) break;
+        i += 1;
+    }
+    connect(sock, (struct sockaddr*)&addr, sizeof(addr));
+    //shutdown(sock, SHUT_WR);
+    for (i = 0; i < 9999; i += 1) {
+        int result = write(sock, spam, 0xffff);
+        if (result < 0) exit(1);
+    }
+}

eagain.zig

@@ -0,0 +1,12 @@
+const std = @import("std");
+
+const path = "eagain.sock";
+const spam: [0xffff]u8 = undefined;
+
+pub fn main() !void {
+    const stream = try std.net.connectUnixSocket(path);
+    _ = try std.posix.fcntl(stream.handle, std.c.F.SETFL, std.c.SOCK.NONBLOCK);
+    for (0..99999) |_| {
+        _ = try stream.write(&spam);
+    }
+}