don't reimplement io.ReadFull

[marten-seemann]

From the documentation:

ReadFull reads exactly len(buf) bytes from r into buf. It returns the number of bytes copied and an error if fewer bytes were read. The error is EOF only if no bytes were read. If an EOF happens after reading some but not all the bytes, ReadFull returns ErrUnexpectedEOF. On return, n == len(buf) if and only if err == nil. If r returns an error having read at least len(buf) bytes, the error is dropped.

Not really sure if we need to convert the io.EOF to io.ErrUnexpectedEOF (only happens if n == 0), but this exactly restores the behavior this function had before.

[Stebalien]

The ErrUnexpectedEOF is correct.

[Stebalien]

non blocking, but @willscott, was there a reason for this?

[willscott]

non blocking, but @willscott, was there a reason for this?

not that I can see. looks like we unintentionally re-implemented io.readfull

[marten-seemann]

Accidentally deleted the branch, reopening.