Trait MemoryReporter 

pub trait MemoryReporter {
    // Required method
    fn heap_memory_bytes(&self) -> usize;

    // Provided method
    fn item_count(&self) -> usize { ... }
}

Trait for components that can report their memory usage.

Implementations should estimate heap memory owned by the component, using capacity() * element_size for collections and size_of::<T>() for fixed-size fields. The goal is a useful approximation, not an exact byte count.

Required Methods

fn heap_memory_bytes(&self) -> usize

Returns estimated heap memory usage in bytes.

This should include:

• Heap allocations owned by this component (Vec capacity, HashMap buckets, etc.)
• Nested heap allocations (String contents, Box contents)

This should NOT include:

• The size of self on the stack (the caller adds that if needed)
• Memory owned by other components (avoid double-counting)

Provided Methods

fn item_count(&self) -> usize

Returns the number of logical items stored.

For a hash map this might be len(), for an index the number of entries, for a cache the number of cached items.

Implementors