in "writeOne" method ,we move foward to next file according to the following condition
if d.writePos >= d.maxBytesPerFile { d.writeFileNum++ ... }
but in "readOne" method,we move foward to next file according to the following condition
if d.nextReadPos > d.maxBytesPerFile { ... d.nextReadFileNum++ }
This may cause an extra read after we finish reading a file, and this read will cause an "EOF" error
in "writeOne" method ,we move foward to next file according to the following condition
if d.writePos >= d.maxBytesPerFile { d.writeFileNum++ ... }
but in "readOne" method,we move foward to next file according to the following condition
if d.nextReadPos > d.maxBytesPerFile { ... d.nextReadFileNum++ }
This may cause an extra read after we finish reading a file, and this read will cause an "EOF" error