code: def test_buffer_donation_method(getkey):
      num_traces = 0
  
      class M(eqx.Module):
          buffer: jax.Array
          mlp: eqx.nn.MLP
  
          def __init__(self, width: int, depth: int):
              self.mlp = eqx.nn.MLP(
                  width, width, width, depth, key=getkey()
              )
              self.buffer = jnp.zeros((100000,))
  
          @eqx.filter_jit(donate="all")
          def __call__(self, x):
              nonlocal num_traces
              num_traces += 1
  
              return self.mlp(x), eqx.tree_at(
                  lambda s: s.buffer, self, self.buffer.at[0].add(1)
              )
  
      m = M(10, 3)
      old_m_p = jtu.tree_map(
          lambda x: x.unsafe_buffer_pointer()
          if hasattr(x, "unsafe_buffer_pointer")
          else None,
          m,
      )
  
      _, new_m = m(jnp.ones((10,)))
      _, new_m = new_m(jnp.ones((10,)))
      _, new_m = new_m(jnp.ones((10,)))
      assert num_traces == 1
  
      assert tree_allclose(new_m.buffer[0], jnp.array(3.0))
      assert m.buffer.is_deleted()
      assert new_m.buffer.unsafe_buffer_pointer() == old_m_p.buffer
  
      old_m_deleted_flag = jtu.tree_map(
          lambda x: x.is_deleted()
          if hasattr(x, "is_deleted")
          else None,
          m,
      )
      for flag in jtu.tree_leaves(old_m_deleted_flag):
          assert flag is True or flag is None
  
imports: import warnings
  from typing import Union
  import equinox
  import jax
  import jax.numpy
  import jax.random
  import jax.tree_util
  import pytest
  from .helpers import tree_allclose
label_desc: Use image node_id 12 for calling a global function with example usage: test_buffer_donation_method(getkey) and returns: self,  eqx