How does Pandas from python reads the timestamp to datetime64? (HDF5)
I'm creating an application on C# that generates a hdf5 document with one row of the compound data being a timestamp (using unix timestamp), and i wish i could load this hdf5 in pandas and it load the timestamp column as a datetime64. I've tried to create the file from pandas and i saw it creates the dataset with a lot of attributes that i assume pandas read and do some logic to convert it while reading the file (the datetime inside the file created from pandas is a timestamp too), i can't figure it out...

Here is my dataset creation code and some screenshots of what i had investigated:

`
public void CriaHDF5Customizado(PackingConfigFile pf)
        {

           // PopulaOPC(pf);

            H5FileId arquivoHDF5 = H5F.create("C:/Users/arthuro/Desktop/timestampteste.h5", H5F.CreateMode.ACC_TRUNC);
            H5GroupId datasetGroup = H5G.create(arquivoHDF5, "Datasets");
            H5GroupId infosGroup = H5G.create(arquivoHDF5, "Informations");
            H5G.close(infosGroup);

            opcSt opHelper = new opcSt();
            opHelper.dt = (Int64)DateTime.Parse("1996-11-9").Subtract(new DateTime(1970, 1, 1,12,00,00, DateTimeKind.Utc)).TotalSeconds;
            opHelper.qlt = (Int64)DateTime.Now.Subtract(new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalSeconds;
            opHelper.vl = 123456.7f;

            
            int structsize = Marshal.SizeOf(opHelper);
            H5DataTypeId myOPCType = H5T.create(H5T.CreateClass.COMPOUND, structsize);
            //H5T.insert(myOPCType, "TimeStamp", 0, new H5DataTypeId(H5T.H5Type.NATIVE_LONG));            
            H5T.insert(myOPCType, "Quality", 8, new H5DataTypeId(H5T.H5Type.NATIVE_LONG));
            H5T.insert(myOPCType, "Value", 16, new H5DataTypeId(H5T.H5Type.NATIVE_FLOAT));


            long[] ds = new long[1];
            ds[0] = 1;
            H5DataTypeId dtDatetime = H5T.create_array(new H5DataTypeId(H5T.H5Type.NATIVE_LLONG), ds);
            H5T.insert(myOPCType, "TimeStamp", 0, dtDatetime);

            foreach (BasicVariable bv in pf.basicVariableList.bvList)
            {
                bv.PopulateOPCUA();
                var bvnow = bv;
                var bvNro = pf.basicVariableList.bvList.IndexOf(bv);
                long[] dims = new long[1];
                dims[0] = bv.bvData.Count;
                H5DataSpaceId myDataSpace = H5S.create_simple(1, dims);
                H5DataSetId bvDset = H5D.create(datasetGroup, bv.bvTag, myOPCType, myDataSpace);
                var arrayaux = new List<opcSt>();
                foreach (OPC_UA opc in bv.bvData)
                {
                    var aux = new opcSt(opc.timeStamp, opc.quality, (float)opc.data);
                    arrayaux.Add(aux);
                }
                H5D.write(bvDset, myOPCType, new H5Array<opcSt>(arrayaux.ToArray()));
                string[] stringteste = { "datetime64" };
                H5DataTypeId attrDt = H5T.copy(H5T.H5Type.C_S1);
                H5T.setSize(attrDt, stringteste[0].Length);
                var longsz = new long[] { 1 };
                var enc = new System.Text.ASCIIEncoding();
                var array1 = enc.GetBytes(stringteste[0]);
                var charArray = new byte[stringteste[0].Length + 1];
                array1.CopyTo(charArray, 0);
                charArray[stringteste[0].Length] = 0;
                H5DataSpaceId atribDS = H5S.create_simple(1, longsz);

                H5AttributeId Attribs = H5A.create(bvDset, "TimeStamp_dtype", attrDt, atribDS);
                H5A.write(Attribs, attrDt, new H5Array<byte>(charArray));

                stringteste[0] = "(lp0L0La.";

                H5T.setSize(attrDt, stringteste[0].Length);
                longsz = new long[] { 1 };
                enc = new System.Text.ASCIIEncoding();
                array1 = enc.GetBytes(stringteste[0]);
                charArray = new byte[stringteste[0].Length + 1];
                array1.CopyTo(charArray, 0);
                charArray[stringteste[0].Length] = 0;
                atribDS = H5S.create_simple(1, longsz);

                H5AttributeId Attribs2 = H5A.create(bvDset, "TimeStamp_kind", attrDt, atribDS);
                H5A.write(Attribs2, attrDt, new H5Array<byte>(charArray));

                stringteste[0] = "N.";

                H5T.setSize(attrDt, stringteste[0].Length);
                longsz = new long[] { 1 };
                enc = new System.Text.ASCIIEncoding();
                array1 = enc.GetBytes(stringteste[0]);
                charArray = new byte[stringteste[0].Length + 1];
                array1.CopyTo(charArray, 0);
                charArray[stringteste[0].Length] = 0;
                atribDS = H5S.create_simple(1, longsz);

                H5AttributeId Attribs3 = H5A.create(bvDset, "TimeStamp_meta", attrDt, atribDS);
                H5A.write(Attribs3, attrDt, new H5Array<byte>(charArray));


                H5S.close(atribDS);
                H5A.close(Attribs);
                H5A.close(Attribs2);
                H5A.close(Attribs3);
                H5D.close(bvDset);
                H5S.close(myDataSpace);
                bv.bvData = new List<OPC_UA>();
            }            

            H5G.close(datasetGroup);
            H5F.close(arquivoHDF5);
        }
`

Pandas reading (timestamp and datetime):

being 1- The value read inside jupyter notebook (processed by pandas) 
          2- The real value inside the HDF5 File

[https://i.stack.imgur.com/ZZJ3A.png](url)

Ahd these are the attributes of the table created by pandas (that i've tried to recreate in my code)

[https://i.stack.imgur.com/U1Zom.png](url)