input: T,C=1,2
co:2
group:2
kernel: OIHW 2,1,1
kernel_as_group_o_ihw: 2,1,1
sum_a: G,O: 2,1
sum_a_reshaped: 1,1,2,1
sum_b: N,G,T 1,2,1
kernel, packed: G,Packed: 2,1
im2col: N,G,P 1,2,1
mmm_output_shape: N,T,G,C 1,1,2,1 m_axis = 3, h_axis = 1
mmm: 1,1,2,1
output: T,C=1,2