class_docstr: Reads/writes `RecordIO` data format, supporting random access.
  
  Examples
  ---------
  >>> for i in range(5):
  ...     record.write_idx(i, 'record_%d'%i)
  >>> record.close()
  >>> record = mx.recordio.MXIndexedRecordIO('tmp.idx', 'tmp.rec', 'r')
  >>> record.read_idx(3)
  record_3
  
  Parameters
  ----------
  idx_path : str
      Path to the index file.
  uri : str
      Path to the record file. Only supports seekable file types.
  flag : str
      'w' for write or 'r' for read.
  key_type : type
      Data type for keys.
docstr: Returns the current position of write head.
  
  Examples
  ---------
  >>> record = mx.recordio.MXIndexedRecordIO('tmp.idx', 'tmp.rec', 'w')
  >>> print(record.tell())
  0
  >>> for i in range(5):
  ...     record.write_idx(i, 'record_%d'%i)
  ...     print(record.tell())
  16
  32
  48
  64
  80
docstr_tok: ["Returns","the","current","position","of","write","head",".","Examples","--","--","--","--","-",">",">",">","record","=","mx.recordio.MXIndexedRecordIO","(","'tmp.idx","'",",","'tmp.rec","'",",","'","w","'",")",">",">",">","print","(","record.tell","(",")",")","0",">",">",">","for","i","in","range","(","5",")",":","...","record.write_idx","(","i",",","'record_","%","d","'","%","i",")","...","print","(","record.tell","(",")",")","16","32","48","64","80"]
code: def tell(self):
      """Returns the current position of write head.
  
      Examples
      ---------
      >>> record = mx.recordio.MXIndexedRecordIO('tmp.idx', 'tmp.rec', 'w')
      >>> print(record.tell())
      0
      >>> for i in range(5):
      ...     record.write_idx(i, 'record_%d'%i)
      ...     print(record.tell())
      16
      32
      48
      64
      80
      """
      assert self.writable
      pos = ctypes.c_size_t()
      check_call(
          _LIB.MXRecordIOWriterTell(self.handle, ctypes.byref(pos))
      )
      return pos.value
  
imports: from collections import namedtuple
  from multiprocessing import current_process
  import ctypes
  import struct
  import numbers
  import numpy
  from .base import _LIB
  from .base import RecordIOHandle
  from .base import check_call
  from .base import c_str
label_desc: Use image node_id 6 for calling the MXIndexedRecordIO obj's underlying member method code with example usage: obj.tell() and returns: pos