why the BiFPN output channel is 256?

[sunlanchang]

# using scaled BiFPN channels did not work in my implementation.
 # here, we use outc=256 for all settings.
outc = 256

In Google's paper the BiFPN channel is 64 in EfficientDet D0 and D2, it is 256 in your code, which confused me a lot. Please explain why you change it to 256. Thanks a lot.

[najingligong1111]

P7_out = self.conv7dw(P7_in + P7_up+F.interpolate(P6_out, P7_up.size()[2:]))

P7_up ？ only two input of P7_out