Memory_mapped.TimeSeriesTime series file format for market data
type header = {magic : int32;version : int32;record_size : int32;record_count : int64;start_time : int64;end_time : int64;symbol_length : int32;reserved : bytes;}File header
val write_header : mmap_handle -> header -> unitval read_header : mmap_handle -> headerval find_timestamp : mmap_handle -> header -> int64 -> int optionval find_time_range : mmap_handle -> header -> int64 -> int64 -> int * int