This seriously improves the serialization/deserialization performance for
several reasons:
* no time spent in `binary` reflection
* no memory allocations being made on every read/write
* uses fast ReadBytes everywhere it's appropriate
It also makes Fixed8 Serializable just for convenience.
reflect.MethodByName is a rather expensive function especially when
called on hot path. This became obvious during profiling of db restore.
This commit replaces reflection with a cast to an interface.
Which speeds it up at least twofold for a typical 32-bytes write (and that's
for a very naïve test that allocates new BufBinWriter on every iteration):
pkg: github.com/CityOfZion/neo-go/pkg/io
BenchmarkWriteBytes-8 10000000 124 ns/op
BenchmarkWriteBytesOld-8 5000000 251 ns/op
golint:
pkg/io/binaryrw_test.go:25:11: should omit type []byte from declaration of var bin; it will be inferred from the right-hand side
pkg/io/binaryrw_test.go:42:11: should omit type []byte from declaration of var bin; it will be inferred from the right-hand side
pkg/io/binaryrw_test.go:118:7: should omit type string from declaration of var str; it will be inferred from the right-hand side
The logic here is that we'll have all binary encoding/decoding done via our io
package, which simplifies error handling. This functionality doesn't belong to
util, so it's moved.
This also expands BufBinWriter with Reset() method to fit the needs of core
package.
