code: def write(self, b: bytes) -> None:
          
          if not isinstance(b, bytes):
              raise TypeError('a bytes-like object is required, not {}'.format(type(b)))
          if not self.std_sim_instance.pause_storage:
              self.byte_buf += b
          if self.std_sim_instance.echo:
              self.std_sim_instance.inner_stream.buffer.write(b)
  
              # Since StdSim wraps TextIO streams, we will flush the stream if line buffering is on
              # and the bytes being written contain a new line character. This is helpful when StdSim
              # is being used to capture output of a shell command because it causes the output to print
              # to the screen more often than if we waited for the stream to flush its buffer.
              if self.std_sim_instance.line_buffering:
                  if any(newline in b for newline in ByteBuf.NEWLINES):
                      self.std_sim_instance.flush()
docs: Add bytes to internal bytes buffer and if echo is True, echo contents to inner stream.