try to raise the number of file descriptors that can be opened to remove limits on number of connected clients (#193)

internal/rlimit/rlimit_unix.go

@@ -0,0 +1,29 @@
+// +build !windows
+
+package rlimit
+
+import (
+	"syscall"
+)
+
+// Raise raises the number of file descriptors that can be opened.
+func Raise() error {
+	var rlim syscall.Rlimit
+	err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rlim)
+	if err != nil {
+		return err
+	}
+
+	rlim.Cur = 999999
+	err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &rlim)
+	if err != nil {
+		return err
+	}
+
+	err = syscall.Getrlimit(syscall.RLIMIT_NOFILE, &rlim)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}