Return the segment index for the largest indexed byte offset <= byteOffset, or -1 if byteOffset precedes the first segment. Exact where an offset matches; otherwise resolves to the segment in progress at that offset.
<= byteOffset
-1
byteOffset
Return the segment index for the largest indexed byte offset
<= byteOffset, or-1ifbyteOffsetprecedes the first segment. Exact where an offset matches; otherwise resolves to the segment in progress at that offset.