code: function marshalPublicKey (jwk) {
    const byteLen = curveLengths[jwk.crv]
  
    return Buffer.concat([
      Buffer.from([4]), // uncompressed point
      toBn(jwk.x).toArrayLike(Buffer, 'be', byteLen),
      toBn(jwk.y).toArrayLike(Buffer, 'be', byteLen)
    ], 1 + byteLen * 2)
  }
docs: Marshal converts a jwk encodec ECDH public key into the form specified in section 4.3.6 of ANSI X9.62. (This is the format go-ipfs uses)