DataErrReader returns a Reader that returns the final error with the last data read, instead of by itself with zero bytes of data.

HalfReader returns a Reader that implements Read by reading half as many requested bytes from r.

NewReadLogger returns a reader that behaves like r except that it logs (using log.Print) each read to standard error, printing the prefix and the hexadecimal data written.

NewWriteLogger returns a writer that behaves like w except that it logs (using log.Printf) each write to standard error, printing the prefix and the hexadecimal data written.

OneByteReader returns a Reader that implements each non-empty Read by reading one byte from r.

TimeoutReader returns ErrTimeout on the second read with no data.

TruncateWriter returns a Writer that writes to w but stops silently after n bytes.