Samples an observation's value.

        Args:
            value: A numeric value signifying the value to be sampled.

def observe(self, value):
        """Samples an observation's value.

        Args:
            value: A numeric value signifying the value to be sampled.
        """
        self._buffer.append(value)
        if len(self._buffer) == _BUFFER_SIZE:
            self._flush()