Flushes all buffers associated with a dataset to disk
herr_t H5Dflush(hid_t dataset_id)
IN: Identifier of the dataset to be flushed
H5D_FLUSH causes all buffers associated with a dataset to be immediately flushed to disk without removing the data from the cache.
HDF5 does not possess full control over buffering. H5D_FLUSH flushes the internal HDF5 buffers and then asks the operating system (the OS) to flush the system buffers for the open files. After that, the OS is responsible for ensuring that the data is actually flushed to disk.
Returns a non-negative value if successful; otherwise returns a negative value.