Macro create_xfs_struct 

macro_rules! create_xfs_struct {
    ($ty:ident, $name:expr, [$($field_name:ident: $field_ty:ident),*], $doc:expr) => { ... };
}

Creates an XFS struct type.

Parameters:

• $ty: the type name of the Rust struct.
• $name: the XFS name of the Rust struct.
• [$field_name: $field_ty]: list of the Rust struct’s field names and types.

NOTE all fields must implement xfs_name, and convert to/from XfsMember.