pub fn is_free(&self, ix: u64) -> bool {
        // note that the terminology in the implementation is locked or unlocked.
        // but our api is allocate/free
        self.header_ptr(ix).is_unlocked()
    }
/// true if the entry at index 'ix' is free (as opposed to being allocated)
true if the entry at index 'ix' is free (as opposed to being allocated)
true if the entry at index ' ix ' is free ( as opposed to being allocated )
pub fn is_free(&self, ix: u64) -> bool {
        // note that the terminology in the implementation is locked or unlocked.
        // but our api is allocate/free
        self.header_ptr(ix).is_unlocked()
    }
pub fn is_free ( & self , ix : u64 ) -> bool { // note that the terminology in the implementation is locked or unlocked. // but our api is allocate/free self . header_ptr ( ix ) . is_unlocked ( ) }
true if the entry at index 'ix' is free (as opposed to being allocated)
true if the entry at index ' ix ' is free ( as opposed to being allocated )
&self
ix
u64