Replace onwrite.bind(undefined, stream) with an arrow function.

Writable creation +29.92%
Duplex creation +19.91%

streams/creation.js kind='duplex' n=50000000 *** 19.91 % ±0.92% ±1.23% ±1.60%
streams/creation.js kind='readable' n=50000000 -0.53 % ±1.14% ±1.53% ±2.01%
streams/creation.js kind='transform' n=50000000 *** 5.06 % ±1.03% ±1.37% ±1.79%
streams/creation.js kind='writable' n=50000000 *** 29.92 % ±1.16% ±1.55% ±2.01%
streams/pipe-object-mode.js n=5000000 0.12 % ±1.16% ±1.55% ±2.04%
streams/pipe.js n=5000000 -0.12 % ±0.80% ±1.07% ±1.39%
streams/writable-manywrites.js len=1024 callback='no' writev='no' sync='no' n=100000 1.82 % ±2.31% ±3.10% ±4.10%
streams/writable-manywrites.js len=1024 callback='no' writev='no' sync='yes' n=100000 -0.77 % ±1.88% ±2.50% ±3.26%
streams/writable-manywrites.js len=1024 callback='no' writev='yes' sync='no' n=100000 0.33 % ±1.24% ±1.66% ±2.17%
streams/writable-manywrites.js len=1024 callback='no' writev='yes' sync='yes' n=100000 0.48 % ±1.48% ±1.97% ±2.56%
streams/writable-manywrites.js len=1024 callback='yes' writev='no' sync='no' n=100000 0.08 % ±0.73% ±0.97% ±1.26%
streams/writable-manywrites.js len=1024 callback='yes' writev='no' sync='yes' n=100000 -2.24 % ±4.73% ±6.36% ±8.42%
streams/writable-manywrites.js len=1024 callback='yes' writev='yes' sync='no' n=100000 -1.10 % ±1.66% ±2.20% ±2.87%
streams/writable-manywrites.js len=1024 callback='yes' writev='yes' sync='yes' n=100000 -0.78 % ±1.58% ±2.11% ±2.75%
streams/writable-manywrites.js len=32768 callback='no' writev='no' sync='no' n=100000 -0.12 % ±0.83% ±1.11% ±1.45%
streams/writable-manywrites.js len=32768 callback='no' writev='no' sync='yes' n=100000 -0.61 % ±1.88% ±2.51% ±3.26%
streams/writable-manywrites.js len=32768 callback='no' writev='yes' sync='no' n=100000 -0.12 % ±0.68% ±0.91% ±1.18%
streams/writable-manywrites.js len=32768 callback='no' writev='yes' sync='yes' n=100000 -1.37 % ±4.54% ±6.10% ±8.04%
streams/writable-manywrites.js len=32768 callback='yes' writev='no' sync='no' n=100000 3.08 % ±4.28% ±5.76% ±7.63%
streams/writable-manywrites.js len=32768 callback='yes' writev='no' sync='yes' n=100000 0.18 % ±1.71% ±2.28% ±2.97%
streams/writable-manywrites.js len=32768 callback='yes' writev='yes' sync='no' n=100000 1.83 % ±3.21% ±4.32% ±5.72%
streams/writable-manywrites.js len=32768 callback='yes' writev='yes' sync='yes' n=100000 0.00 % ±1.64% ±2.19% ±2.86%

Be aware that when doing many comparisons the risk of a false-positive
result increases. In this case, there are 22 comparisons, you can thus
expect the following amount of false-positive results:
1.10 false positives, when considering a 5% risk acceptance (*, **, *),
0.22 false positives, when considering a 1% risk acceptance (, ),
0.02 false positives, when considering a 0.1% risk acceptance ()