does mojo have access modifiers

for example in rust :

struct Foo{
  pub public_member:u32
  private_member:u32
}

struct Foo{
  pub public_member:u32
  private_member:u32
}

struct Foo{
  pub public_member:u32
  private_member:u32
}

struct Foo{
  pub public_member:u32
  private_member:u32
}