void setFloat64(
int byteOffset,
double value,
[Endianness endian = Endianness.BIG_ENDIAN]
)

Sets the eight bytes starting at the specified byteOffset in this object to the IEEE 754 double-precision binary floating-point (binary64) representation of the specified value.

Throws RangeError if byteOffset is negative, or byteOffset + 8 is greater than the length of this object.

Source

/**
 * Sets the eight bytes starting at the specified [byteOffset] in this
 * object to the IEEE 754 double-precision binary floating-point
 * (binary64) representation of the specified [value].
 *
 * Throws [RangeError] if [byteOffset] is negative, or
 * `byteOffset + 8` is greater than the length of this object.
 */
void setFloat64(int byteOffset,
                double value,
                [Endianness endian = Endianness.BIG_ENDIAN]);