Problem:
```
--- FAIL: TestMakeDirForFile_HappyPath (0.01s)
testing.go:894: TempDir RemoveAll cleanup: remove C:\Users\Anna\AppData\Local\Temp\TestMakeDirForFile_HappyPath402638411\001\testDir\testFile.test: The process cannot access the file because it is being used by another process.
--- FAIL: TestMakeDirForFile_Negative (0.01s)
testing.go:894: TempDir RemoveAll cleanup: remove C:\Users\Anna\AppData\Local\Temp\TestMakeDirForFile_Negative672737582\001\testFile.test: The process cannot access the file because it is being used by another process.
FAIL
```
Solution:
Release resources occupied by os.Create.
Similar to c69670c85b, allows to eliminate one
allocation and reduce memory footprint a bit (tested on tx decoding):
name old time/op new time/op delta
DecodeFromBytes-8 1.78µs ± 3% 1.79µs ± 2% ~ (p=1.000 n=10+10)
name old alloc/op new alloc/op delta
DecodeFromBytes-8 888B ± 0% 800B ± 0% -9.91% (p=0.000 n=10+10)
name old allocs/op new allocs/op delta
DecodeFromBytes-8 11.0 ± 0% 10.0 ± 0% -9.09% (p=0.000 n=10+10)
This reverts commit 168ba7960c.
It seems, there are some problems with it:
`2020-12-25T18:13:07.476+0300 WARN blockQueue: failed adding block into the blockchain {"error": "error while trying to apply MPT changes: unexpected EOF", "blockHeight": 9729, "nextIndex": 9730}`
Running time becomes faster under high load while staying the same in
the average case.
Memory allocation done in `Trie` goes down by about ~10% (even more,
actually).
go vet is not happy about them:
pkg/io/binaryReader.go:92:21: method ReadByte() byte should have signature ReadByte() (byte, error)
pkg/io/binaryWriter.go:75:21: method WriteByte(u8 byte) should have signature WriteByte(byte) error
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.
It can't be really solved in many cases (it's used in P2P protocol and we have
to follow the usual conventions there) and in most of the cases we don't care
about the difference between nil slice and zero-length slice.
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
It's mostly used for Serializable and in other cases where one needs to
estimate binary-encoded size of the stucture. This also simplifies future
removal of the Size() from Serializable.
