Possibly optimize binary reader

[timostamm]

BinaryReader.bytes() uses slice() to extract byte field data:

return this.buf.slice(start, this.pos);

According to MDN, this creates a copy:

The slice method does not alter the original typed array, but instead returns a copy of a portion of the original typed array.

Since we do not need a copy, it should be possible to replace this with:

return new Uint8Array(this.buf.buffer, this.buf.byteOffset + start, len);

Which will not allocate additional memory and does not require a copy.

[timostamm]

We are now using subarray() (equivalent to creating a Uint8Array like above).